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fix: normalize Anthropic PascalCase MCP tool names - #16820

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fix: normalize Anthropic PascalCase MCP tool names#16820
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irispillars:fix/16817-mcp-pascalcase-normalization

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@irispillars

@irispillars irispillars commented Apr 28, 2026

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Summary

Fixes Anthropic transport tool-name normalization for Claude Code-shaped MCP response names.

When an Anthropic/OAuth route returns a tool-use name like mcp_Terminal, Hermes strips the mcp_ prefix but currently leaves Terminal, which does not match the registered Hermes tool name terminal.

This PR lowercases the first character after stripping mcp_ when needed, preserving existing lowercase behavior while supporting Claude Code-shaped PascalCase tool names.

Fixes #16817

Test Plan

  • python -m py_compile agent/transports/anthropic.py tests/agent/test_anthropic_adapter.py
  • python -m pytest -q tests/agent/test_anthropic_adapter.py::TestAnthropicTransportToolNormalization tests/agent/test_anthropic_adapter.py::TestToolChoice
  • Ran the full tests/agent/test_anthropic_adapter.py locally; it exposed pre-existing environment/config failures unrelated to this change (local macOS Claude keychain credentials leaking into tests and an existing beta-header expectation mismatch), while the new focused regression passed.

Notes

This PR does not promote or install any admin/OAuth route. It only hardens response normalization for Claude Code-shaped mcp_ tool names.

@irispillars

irispillars commented Apr 28, 2026

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CI note for review:

  • This PR only changes:
    • agent/transports/anthropic.py
    • tests/agent/test_anthropic_adapter.py
  • PR-scoped local verification passed:
    • python -m py_compile agent/transports/anthropic.py tests/agent/test_anthropic_adapter.py
    • python -m pytest -q tests/agent/test_anthropic_adapter.py::TestAnthropicTransportToolNormalization tests/agent/test_anthropic_adapter.py::TestToolChoice
  • The full Tests workflow is red on this PR, but recent main pushes are also red on the same workflow. I verified the latest five main runs for Tests are failing/cancelled, so the CI suite appears currently unstable independent of this two-file normalization patch.

I’m leaving the PR open for maintainer review rather than expanding this narrow fix to chase unrelated suite failures.

@alt-glitch alt-glitch added type/bug Something isn't working P2 Medium — degraded but workaround exists comp/agent Core agent runtime: loop, agent_init, prompt builder, context-compression, responses endpoint provider/anthropic Anthropic native Messages API tool/mcp MCP client and OAuth labels Apr 28, 2026
@teknium1 teknium1 mentioned this pull request Apr 28, 2026
Merged
teknium1 added a commit that referenced this pull request Apr 28, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
023f5c7 
… API path (#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes #16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
@teknium1

teknium1 commented Apr 28, 2026

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Superseded by #16957 — we removed the entire Claude Code spoofing layer from the Anthropic OAuth Messages path (system-prompt prefix, Hermes→Claude Code substitutions, and the mcp_ tool-name round-trip). With the mcp_ prefix no longer sent outbound, the PascalCase dispatch failure your patch fixed can no longer occur on this path, so the normalization patch is moot.

Thanks for the careful investigation — your regression case (mcp_Terminal → terminal) was exactly the kind of symptom that made the spoofing layer look fragile and pushed us to audit it. Verified live against api.anthropic.com with a fresh OAuth token: the de-spoofed path accepts Hermes identity + plain tool names cleanly (HTTP 200, tool_use round-trip works).

#16957

@teknium1 teknium1 closed this Apr 28, 2026
cluricaun28 referenced this pull request in cluricaun28/Logos Apr 28, 2026
@teknium1 @Teknium Patrick Daley
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
e85843b 
… API path (#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes #16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
donald131 pushed a commit to donald131/hermes-agent that referenced this pull request May 2, 2026
@teknium1 @Teknium zy
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
9972967 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
02356abc pushed a commit to 02356abc/hermes-agent that referenced this pull request May 14, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
c21a900 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
dannyJ848 pushed a commit to dannyJ848/hermes-agent that referenced this pull request May 17, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
6d870f0 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
gweeteve pushed a commit to gweeteve/hermes-agent that referenced this pull request Jun 2, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
27b193f 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
Seven74AI pushed a commit to Seven74AI/hermes-agent that referenced this pull request Jun 13, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
df6d151 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
waefrebeorn pushed a commit to waefrebeorn/slermes that referenced this pull request Jul 2, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
f672eea 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
Gravezzz pushed a commit to Gravezzz/hermes-agent that referenced this pull request Jul 21, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
1bcb69e 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
prmartinow pushed a commit to prmartinow/hermes-agent that referenced this pull request Aug 26, 2026
@teknium1 @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
9f467fa 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
melon-xf added a commit to melon-xf/hermes-agent that referenced this pull request Sep 3, 2026
@melon-xf @Teknium
fix(anthropic): remove Claude Code fingerprinting from OAuth Messages…
c62fccb 
… API path (NousResearch#16957)

* fix(anthropic): remove Claude Code fingerprinting from OAuth Messages API path

OAuth requests now identify as Hermes on the wire. Removed:

  - "You are Claude Code, Anthropic's official CLI for Claude." system
    prompt prepend
  - Hermes Agent → Claude Code / Nous Research → Anthropic
    system-prompt substitutions
  - mcp_ tool-name prefix on outgoing tool schemas + message history
  - Matching mcp_ strip on inbound tool_use blocks (strip_tool_prefix path
    removed from AnthropicTransport.normalize_response, + all 5 call
    sites in run_agent.py and auxiliary_client.py)
  - user-agent: claude-cli/<v> (external, cli) and x-app: cli headers on
    the Messages API client

Added:

  - OAuth path strips context-1m-2025-08-07 — Anthropic rejects OAuth
    requests carrying it with HTTP 400 'This authentication style is
    incompatible with the long context beta header.'

Kept (auth plumbing, not identity spoofing):

  - _is_oauth_token classifier and is_oauth flag threading
  - Bearer vs x-api-key auth routing
  - _OAUTH_ONLY_BETAS (claude-code-20250219, oauth-2025-04-20) — backend
    requires these on the OAuth-gated Messages endpoint
  - _OAUTH_CLIENT_ID (Claude Code's) — Anthropic doesn't issue OAuth
    creds to third parties; this is the only way the login flow works
  - claude-cli/<v> User-Agent on the OAuth token exchange + refresh
    endpoints at platform.claude.com/v1/oauth/token — bare requests get
    Cloudflare 1010 blocked

Verified live against api.anthropic.com with a fresh sk-ant-oat01-*
token:

  - claude-haiku-4-5 simple message: HTTP 200, 'OK' response
  - claude-haiku-4-5 tool call: HTTP 200, stop_reason=tool_use, tool
    named 'terminal' (no mcp_ prefix) round-tripped correctly
  - Outgoing wire: no user-agent, no x-app, real Hermes identity in
    system prompt, real tool name in schema

Closes/supersedes NousResearch#16820 (mcp_ PascalCase normalization patch — no longer
needed since the mcp_ round-trip is gone).

* fix(anthropic): resolve_anthropic_token() reads credential pool first

Close the gap where ~/.hermes/auth.json → credential_pool.anthropic
(where hermes login + dashboard PKCE flow write OAuth tokens) was not
in resolve_anthropic_token()'s source list.

Before: users who authed via hermes login got the token written into
the pool, but legacy fallback code paths (auxiliary_client, models
catalog fetch, explicit-runtime path) that call resolve_anthropic_token()
saw None and raised 'No Anthropic credentials found' — even though the
token was sitting in auth.json.

New priority 1: pool.select() with env-sourced entries skipped. Skipping
env:* entries preserves the existing env-var priority logic further
down the chain (static env OAuth → refreshable Claude Code upgrade via
_prefer_refreshable_claude_code_token).

Surfaced while writing the hermes-agent-dev skill playbook for
'finding a live OAuth token for an E2E test'.

---------

Co-authored-by: teknium1 <teknium@users.noreply.github.com>
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comp/agent Core agent runtime: loop, agent_init, prompt builder, context-compression, responses endpoint P2 Medium — degraded but workaround exists provider/anthropic Anthropic native Messages API tool/mcp MCP client and OAuth type/bug Something isn't working

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Anthropic MCP PascalCase tool responses do not normalize to registered tool names

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@irispillars @teknium1 @alt-glitch