Add read-only MCP boundary and path-containment regression tests

[rajudandigam]

Contribution lane: testing / mcp
Difficulty: advanced
Ownership: community-owned
Priority: p1
Milestone: Evidence v2 & CI
Labels: testing, area:mcp, integration:mcp, community-owned, status:ready, difficulty:advanced, priority:p1, support:supported
Baseline: agent-inspect@6.17.1 → 6.18.0 niche launch

Problem

Read-only MCP needs regression tests for boundary and path-containment (no writes, no escape from allowed roots).

Why it matters

MCP exposure is high-risk; niche launch requires hard regressions.

Proposed scope

• Add regression tests for read-only tool surface and path containment.
• Attempt traversal / write / disallowed path cases safely.
• Keep tests local.

Out of scope

• Write MCP tools
• Remote MCP hosting
• Weakening containment

Suggested files

• MCP server/tests
• Security docs

Acceptance criteria

• Write attempts rejected
• Path escape attempts rejected
• Focused tests pass

Validation commands

pnpm exec vitest run <relevant>
git diff --check

Privacy / network notes

Local only. No egress. Synthetic paths.

Contributor instructions

Comment first. Prefer table-driven cases.

Maintainer-review boundary

Maintainers own MCP security boundary changes.