docs(rfc): rfc 0026 authn/tenant binding + rfc 0027 mcp query surface

[jensholdgaard]

Two drafted designs (§§1–4 + 7–8 per the lifecycle) for the exposure workstream:

RFC 0026 — Authentication & tenant binding. Closes RFC 0003 §9 and RFC 0016's deferred authn: static bearer tokens via the RFC 0020 config (${env} indirection), enforced on both OTLP listeners and the query API. The authz core: each token carries an allowed tenant set; ingest keeps attribute-derived tenancy (§6.3 unchanged) but the derived tenant must fall in the token's set, rejected before the WAL ack; query validates x-ourios-tenant against the same set, composing with (never replacing) the structural partition scoping. No-auth-section = today's open mode with a startup warning.

RFC 0027 — MCP query surface. Agent-facing read tools (query_logs, list_templates, template_drift + the DSL grammar as a resource) over the querier's existing machinery; streamable HTTP at /mcp on the existing listener, module in ourios-server (no new crate), default off. Read-only, no SQL escape hatch (hazard §4.6), and implementation gated on RFC 0026. Documents the returned-log-bodies-are-untrusted-text hazard for LLM consumers.

Sign-off order when you're ready: 0026 first (0027's gate).

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Summary by CodeRabbit

• Documentation
  • Added new RFC documentation covering upcoming authentication and tenant-based access controls.
  • Added new RFC documentation for a read-only MCP query surface for querying data.
  • Updated the RFC index to include the new entries.

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Review details

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 10be521e-df54-4348-88f8-339a7279a1f8

📥 Commits

Reviewing files that changed from the base of the PR and between 28e3f0a and abe2dfa.

📒 Files selected for processing (2)

• docs/rfcs/0026-authentication-tenant-binding.md
• docs/rfcs/0027-mcp-query-surface.md

📝 Walkthrough

Walkthrough

This PR adds two new RFC documents: RFC 0026 defining bearer-token authentication and tenant binding for ingest and query, and RFC 0027 defining an MCP read-only query surface gated by RFC 0026 auth. The docs SUMMARY.md index is updated to link both.

Changes

RFC documentation additions

Layer / File(s)	Summary
RFC 0026: Authentication & tenant binding docs/rfcs/0026-authentication-tenant-binding.md	Documents bearer-token auth config, ingest/query tenant enforcement before WAL append, telemetry/audit behavior, alternatives, acceptance criteria, and open questions.
RFC 0027: MCP query surface docs/rfcs/0027-mcp-query-surface.md	Documents an MCP read-only query surface at /mcp, gated by RFC 0026 auth, covering tool set, output discipline, alternatives, acceptance criteria, and open questions.
Docs index update docs/SUMMARY.md	Adds links to RFC 0026 and RFC 0027 in the RFCs list.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• epic: authn for the data-plane APIs — OIDC/bearer/mTLS, verified tenant binding (receiver + querier) #331: Adds an RFC for authentication and tenant binding overlapping with this issue's authn/tenant-binding scope for receiver/querier APIs.
• epic: built-in MCP server (explore) — expose the query surface to LLM agents #323: RFC 0027 addresses this issue's built-in MCP server idea, with RFC 0026 providing the auth/tenant-binding dependency it calls out.

Possibly related PRs

• jensholdgaard/ourios#259: RFC 0016 defines the querier HTTP endpoint with tenant scoping that RFC 0026 extends with bearer-token authentication and tenant binding.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description covers the RFC changes, but it omits the template's Related and Checklist sections and doesn't use the required headings.	Add the ## Related section and the checklist items from the template, and format the description with the repository's required headings.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the two RFC additions and their focus on auth/tenant binding and the MCP query surface.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch rfc0026-0027-drafts

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[Copilot]

Pull request overview

Adds two new drafted RFC design documents for the “exposure” workstream: (1) introducing bearer-token authentication with tenant binding for ingest + query, and (2) defining an MCP (Model Context Protocol) read-only query surface layered on the existing querier API and explicitly gated on the authn work.

Changes:

• Add RFC 0026 detailing static bearer-token authn plus token-to-tenant allow-list enforcement for both ingest and query.
• Add RFC 0027 specifying an MCP server endpoint (/mcp) exposing typed, agent-facing read tools over the querier, gated on RFC 0026.
• Update the docs book summary to include RFC 0026 and RFC 0027.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
docs/SUMMARY.md	Adds RFC 0026 and RFC 0027 to the documentation index.
docs/rfcs/0026-authentication-tenant-binding.md	Drafted RFC describing authn and tenant-binding enforcement design for ingest + query.
docs/rfcs/0027-mcp-query-surface.md	Drafted RFC describing an MCP query surface hosted on the querier listener, gated on RFC 0026.

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@docs/rfcs/0026-authentication-tenant-binding.md`:
- Around line 108-111: Clarify the query-path status code contract in the RFC so
it matches the behavior in querier logic: missing or empty x-ourios-tenant
should be documented as a 400, while only a provided tenant that is not in the
token’s allowed set should be a 403. Update the wording around the HTTP query
API rule to separate these cases clearly, and align the description with the
behavior implemented in querier.rs and the relevant tenant-binding checks.

In `@docs/rfcs/0027-mcp-query-surface.md`:
- Around line 71-73: Clarify the interval semantics for template_drift by
stating whether the from/to bounds are inclusive or half-open in the RFC entry
for that query surface. Update the description near template_drift to make the
boundary rule explicit using the existing query name and argument names (tenant,
from, to), so implementers know exactly how to interpret the range.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: b073f810-1148-4b6b-ae9f-bcb993f0a3e4

📥 Commits

Reviewing files that changed from the base of the PR and between 1a4db29 and 28e3f0a.

📒 Files selected for processing (3)

• docs/SUMMARY.md
• docs/rfcs/0026-authentication-tenant-binding.md
• docs/rfcs/0027-mcp-query-surface.md

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.