fix: classify OpenRouter 'no endpoints found that support tool use' 404 as model_not_found with fallback by webtecnica · Pull Request #58451 · NousResearch/hermes-agent

webtecnica · 2026-07-04T18:52:14Z

Problem

When OpenRouter routes to an endpoint that does not support tool/function calling, it returns HTTP 404:

No endpoints found that support tool use. Try disabling "browser_back".
To learn more about provider routing, visit:
https://openrouter.ai/docs/guides/routing/provider-selection

The raw error body does not contain "model not found" or any other _MODEL_NOT_FOUND_PATTERNS entry, so it falls through to FailoverReason.unknown with retryable=True. The retry loop wastes 3–5 attempts on the same deterministic rejection, then surfaces a confusing generic error instead of automatically failing over to a fallback model or provider.

Fix

Added the OpenRouter phrase "no endpoints found that support tool use" to _MODEL_NOT_FOUND_PATTERNS in agent/error_classifier.py.

This classifies the error as model_not_found (retryable=False, should_fallback=True), which triggers the client-error fast-fallback path in conversation_loop.py: the agent switches to a configured fallback model/provider before the user ever sees the error.

What doesn't change

Existing buffered guidance in conversation_loop.py (the "support tool use" hint at line ~2967) remains intact — it surfaces only if every fallback exhausts.
The _PROVIDER_POLICY_BLOCKED_PATTERNS are unaffected — those are distinct OpenRouter errors about data/privacy guardrails where fallback would not help.

Testing

✅ Pattern matches the exact OpenRouter error body (confirmed from user reports)
✅ Classifier returns model_not_found → retryable=False, should_fallback=True
✅ This triggers is_client_error → _try_activate_fallback() in the retry loop
✅ The existing "support tool use" hint at conversation_loop.py:2967 still fires as a fallback safeguard

- package-lock.json changes in #58451 were unrelated peer-flag churn - CANONICAL_PROVIDERS 'poolside' entry from #58374 has no ProviderConfig in hermes_cli/auth.py and no setup flow, so the picker entry would be dead; the wire-format coercions stand on their own

…llback When OpenRouter routes to an endpoint that does not support tool/function calling, it returns HTTP 404 with the message 'No endpoints found that support tool use. Try disabling "browser_back".' The raw error body does not contain 'model not found' or any other _MODEL_NOT_FOUND_PATTERNS entry, so it falls through to FailoverReason.unknown with retryable=True. The retry loop wastes 3-5 attempts on the same deterministic rejection, then surfaces a confusing generic error instead of automatically failing over to a fallback model or provider. Adding the OpenRouter phrase to _MODEL_NOT_FOUND_PATTERNS classifies it as model_not_found (retryable=False, should_fallback=True), which triggers the client-error fast-fallback path in conversation_loop.py: the agent switches to a configured fallback model/provider before the user sees the error. Existing buffered guidance in conversation_loop.py (the 'support tool use' hint at line ~2967) remains intact and surfaces only if every fallback exhausts.

webtecnica · 2026-07-04T22:33:30Z

Update: diff limpo + teste de regressão

Rebaseei no main mais recente e fiz duas melhorias:

Removi o package-lock.json noise — o diff agora tem só 2 arquivos, +24 linhas (apenas error_classifier.py + teste).
Adicionei teste de regressão — test_404_openrouter_tool_use_not_supported em tests/agent/test_error_classifier.py. Verifica que a mensagem exata do OpenRouter classifica como model_not_found com retryable=False, should_fallback=True.

Todos os 180 testes do error_classifier passam. 👌

- package-lock.json changes in #58451 were unrelated peer-flag churn - CANONICAL_PROVIDERS 'poolside' entry from #58374 has no ProviderConfig in hermes_cli/auth.py and no setup flow, so the picker entry would be dead; the wire-format coercions stand on their own

- package-lock.json changes in NousResearch#58451 were unrelated peer-flag churn - CANONICAL_PROVIDERS 'poolside' entry from NousResearch#58374 has no ProviderConfig in hermes_cli/auth.py and no setup flow, so the picker entry would be dead; the wire-format coercions stand on their own

…n error quirks Adds a plugin seam at the top of agent/error_classifier.classify_api_error() (step 0, before the built-in pipeline) so model-provider plugins can classify their provider's error quirks without patching core: - New "classify_api_error" entry in VALID_HOOKS. Callbacks receive the parsed error context (provider, model, status_code, error_type, error_code, error_message, error_body, error, approx_tokens, context_length, num_messages), self-scope on `provider`, and return None to pass or a dict {"reason": "<FailoverReason name>", ...optional recovery-hint overrides}. - get_plugin_error_classification() helper mirrors get_pre_tool_call_block_message(): first valid result wins, invalid dicts and unknown reasons are skipped, callback exceptions are isolated — a broken plugin can never break classification. Zero behavior change when no plugin claims the error (all 179 existing classifier tests pass untouched). - Bundled reference plugin `openrouter-tool-use-404` (opt-in, like all bundled standalone plugins) re-implements PR NousResearch#58451: OpenRouter's "No endpoints found that support tool use" 404 carries no _MODEL_NOT_FOUND_PATTERNS signal, so it classifies as unknown/retryable and the retry loop burns 3-5 attempts on a deterministic rejection. The plugin classifies it as model_not_found (retryable=False, should_fallback=True) so the fast-fallback path fires immediately — demonstrating a waiting core PR converted to a publishable plugin. Motivation: ~10 open PRs are single-provider error-classification patches (NousResearch#58451, NousResearch#58355, NousResearch#58502, NousResearch#58474, NousResearch#58366, ...). This hook turns that whole class of contribution into plugin territory. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FWMcB7RPSYUpsXDfBgwjzM

…n error quirks Adds a plugin seam at the top of agent/error_classifier.classify_api_error() (step 0, before the built-in pipeline) so model-provider plugins can classify their provider's error quirks without patching core: - New "classify_api_error" entry in VALID_HOOKS. Callbacks receive the parsed error context (provider, model, status_code, error_type, error_code, error_message, error_body, error, approx_tokens, context_length, num_messages), self-scope on `provider`, and return None to pass or a dict {"reason": "<FailoverReason name>", ...optional recovery-hint overrides}. - get_plugin_error_classification() helper mirrors get_pre_tool_call_block_message(): first valid result wins, invalid dicts and unknown reasons are skipped, callback exceptions are isolated — a broken plugin can never break classification. Zero behavior change when no plugin claims the error (all 179 existing classifier tests pass untouched). - Bundled reference plugin `openrouter-tool-use-404` (opt-in, like all bundled standalone plugins) re-implements PR #58451: OpenRouter's "No endpoints found that support tool use" 404 carries no _MODEL_NOT_FOUND_PATTERNS signal, so it classifies as unknown/retryable and the retry loop burns 3-5 attempts on a deterministic rejection. The plugin classifies it as model_not_found (retryable=False, should_fallback=True) so the fast-fallback path fires immediately — demonstrating a waiting core PR converted to a publishable plugin. Motivation: ~10 open PRs are single-provider error-classification patches (#58451, #58355, #58502, #58474, #58366, ...). This hook turns that whole class of contribution into plugin territory. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FWMcB7RPSYUpsXDfBgwjzM

webtecnica requested a review from a team July 4, 2026 18:52

alt-glitch added type/bug Something isn't working comp/agent Core agent runtime: loop, agent_init, prompt builder, context-compression, responses endpoint provider/openrouter OpenRouter aggregator P2 Medium — degraded but workaround exists labels Jul 4, 2026

teknium1 mentioned this pull request Jul 4, 2026

fix(providers): aux pool fallback, tool-use 404 classification, poolside wire types, codex text recovery (4-PR salvage) #58502

Merged

webdevtodayjason mentioned this pull request Jul 4, 2026

feat(plugins): transform_api_error_classification hook so provider plugins own their error quirks #58524

Closed

webtecnica added 2 commits July 4, 2026 19:33

test: add regression test for OpenRouter tool-use 404 classification

48590ca

webtecnica force-pushed the fix/openrouter-tool-use-404-fallback branch from 9f92ab6 to 48590ca Compare July 4, 2026 22:33

teknium1 closed this in #58502 Jul 4, 2026

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fix: classify OpenRouter 'no endpoints found that support tool use' 404 as model_not_found with fallback - #58451

fix: classify OpenRouter 'no endpoints found that support tool use' 404 as model_not_found with fallback#58451
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webtecnica commented Jul 4, 2026

Problem

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What doesn't change

Testing

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webtecnica commented Jul 4, 2026

Update: diff limpo + teste de regressão

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