---
id: review-002-con17-mcp-pagination
name: Bound MCP tools/list pagination (max pages + deadline) (CON-14)
status: completed
depends_on: []
scope: narrow
risk: low
impact: component
level: implementation
tags: [adapters, review-002, mcp]
---

## Description

Review 002 CON-14 [major]. `from_mcp/mod.rs:114-119` delegates to
rmcp 1.8.0's `Peer::list_all_tools`, which loops `while
cursor.is_some()` with **no page cap and no timeout** (verified against
rmcp source `service/client.rs:390-407`). A malicious or buggy server
that always returns `next_cursor: Some(...)` (cycling or ignoring the
cursor) hangs `import()` indefinitely while appending every page's
tools → unbounded memory growth alongside the hang. Tools from
completed pages are not lost (extend per page), but nothing in alkhttp
bounds the loop. The paging test that exists (from_mcp_integration.rs)
terminates after 3 pages — the cycling shape is untested.

## Acceptance Criteria

- [ ] Replace `list_all_tools` with a bounded loop over `list_tools`:
      hard page-count cap + overall deadline (constants or config;
      pick generous defaults — e.g. 100 pages / 60 s — and note them
      in the module doc)
- [ ] Budget trips → `AdapterError::DiscoveryFailed`-family error
      naming the budget (pages seen, tools accumulated), no partial
      import left behind (the existing import-fails-closed behavior
      holds)
- [ ] Integration test: a paging server that cycles its cursor
      (always `next_cursor: Some("a")`) → import terminates with the
      clean error, bounded time (no hang)
- [ ] Existing 3-page pagination test unchanged and passing
      (well-formed pagination still imports all pages)
- [ ] `cargo test --features mcp`, `cargo clippy --all-features --all-targets -- -D warnings`,
      `cargo fmt --check` pass

## References

- docs/reviews/002-post-remediation-review.md (Part F', CON-14)
- src/adapters/from_mcp/mod.rs:114-119 (the delegation), rmcp 1.8.0 src/service/client.rs:390-407 (the unbounded loop)
- tests/from_mcp_integration.rs:302-317 (the existing paging server)
- tasks/adapters/review-001-consumer-adapter-hygiene.md (CON-01's pagination work this bounds)

## Notes

Small, self-contained, feature-gated (`mcp`). Consider (optional) a
`max_tools` sanity cap as well — same budget family, one more guard
against a hostile server — but do not let scope creep: the page cap +
deadline closes the hang, which is the finding.

## Summary

list_all_tools_bounded replaces rmcp's unbounded list_all_tools: 100-page cap + 60s deadline (per-page timeout sized to remaining budget), loud DiscoveryFailed naming both budgets on trip, fail-closed import. Cycling-cursor integration test (previously hung forever).