fix(mcp): bound opportunity target fanout

[JSONbored]

Motivation

• Prevent authenticated callers from amplifying D1/Worker/GitHub work by submitting unbounded or duplicated targets to the opportunity discovery flow.
• Ensure the MCP tool and HTTP route reject oversized input early and that deduplication happens before any per-target authorization or repository lookup.

Description

• Added shared limits and constants exported from src/mcp/find-opportunities.ts: MAX_FIND_OPPORTUNITIES_TARGETS, MAX_FIND_OPPORTUNITIES_OWNER_LENGTH, MAX_FIND_OPPORTUNITIES_REPO_LENGTH, MAX_FIND_OPPORTUNITIES_LANGUAGES, and MAX_FIND_OPPORTUNITIES_LANGUAGE_LENGTH and used them in validation.
• Updated validateFindOpportunitiesInput to trim, validate, cap, and deduplicate targets and to validate language input before returning, and to return normalized targets for downstream use.
• Applied the same caps to the MCP tool Zod schema in src/mcp/server.ts so oversized MCP requests are rejected at the tool boundary.
• Classified /v1/opportunities/find as an expensive route in src/auth/rate-limit.ts to reduce rate-limit abuse amplification, and added regression tests covering caps, deduplication, MCP rejection, and route classification.

Testing

• Ran unit tests with npx vitest run test/unit/find-opportunities.test.ts test/unit/mcp-find-opportunities.test.ts test/unit/auth.test.ts and all selected tests passed.
• Ran git diff --check as a preflight sanity check and it succeeded.
• Attempted targeted coverage collection (npm run test:coverage for the selected tests) and the selected tests ran but coverage remapping failed with TypeError: jsTokens is not a function after the tests completed.
• Ran npx tsc --noEmit which surfaced pre-existing unrelated syntax errors in src/queue/processors.ts and is not caused by this change.

---

Codex Task

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.66%. Comparing base (95d2113) to head (4eb8e47).
⚠️ Report is 12 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4072   +/-   ##
=======================================
  Coverage   93.65%   93.66%           
=======================================
  Files         384      384           
  Lines       35865    35886   +21     
  Branches    13160    13168    +8     
=======================================
+ Hits        33589    33612   +23     
  Misses       1618     1618           
+ Partials      658      656    -2     

Files with missing lines	Coverage Δ
src/auth/rate-limit.ts	98.83% <ø> (ø)
src/mcp/find-opportunities.ts	73.50% <100.00%> (+7.87%)	⬆️
src/mcp/server.ts	94.91% <ø> (ø)

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[loopover-orb]

Warning

🟨🟨🟨🟨🟨🟨🟨🟨🟨🟨🟨🟨

⏸️ Gittensory review result - manual review recommended

_{Review updated: 2026-07-08 05:18:33 UTC}

6 files · 2 blockers · readiness 93/100 · CI green · clean

⏸️ Suggested Action - Manual Review

• No linked issue detected — If this PR is intended to solve an issue, link it explicitly in the PR body.
• Maintainer requires a linked issue — Link the relevant issue (for example Closes #123) before opening the PR.

Concerns raised — review before merging

• No linked issue detected — If this PR is intended to solve an issue, link it explicitly in the PR body.
• Maintainer requires a linked issue — Link the relevant issue (for example Closes #123) before opening the PR.

Signal	Result	Evidence
Code review	❌ 2 blockers	No AI review summary
Linked issue	⚠️ Missing	No linked issue or no-issue rationale found.
Related work	✅ No active overlap found	No same-issue or scoped active PR overlap found.
Change scope	✅ 20/20	Low review scope from cached public metadata (no linked issue context).
Validation posture	✅ 25/25	PR body includes validation/test evidence.
Contributor workload	✅ 10/10	Author activity: 51 registered-repo PR(s), 43 merged, 505 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	JSONbored; Gittensor profile; 51 PR(s), 505 issue(s).
Gate result	❌ Blocking	Repo-configured hard blocker found.

Review context

• Author: JSONbored
• Role context: owner (maintainer lane)
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: Python, TypeScript, JavaScript, Ruby, Go, Kotlin, MDX, Shell
• Official Gittensor activity: 51 PR(s), 505 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Treat this as maintainer-lane context rather than normal contributor-lane activity.
• Explain no-issue PR.
• Link the issue being solved, or explicitly explain why this is a no-issue PR.

Signal definitions

• Related work = same linked issue, overlapping active PRs, or title/path similarity.
• Change scope = cached public metadata such as size labels, draft state, and review-burden hints.
• Validation posture = whether the PR provides enough public validation/test evidence for maintainer review.
• Contributor workload = public contributor activity and cleanup pressure, not a repo-wide quality failure.
• Contributor context = public GitHub/Gittensor identity context; non-Gittensor status is not a blocker.

_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed}

---

💰 Earn for open-source contributions like this. Gittensor lets GitHub contributors earn for the work they already do — register to start earning →.

Checked by Gittensory, a quiet PR intelligence layer for OSS maintainers.

• Re-run Gittensory review