F0.1 — Performance budgets & workflow scope
The explicit performance contract for the program. Numbers are targets, measured on the large local fixture (F0.4) via the harness (F9.1), warm cache excluded unless noted. p50/p95 are server-side latency for the API call; CLI/MCP add transport + (de)serialization on top, which is why payload ceilings and connection reuse (F4.2) matter as much as query time.Latency budgets (hot workflows)
| Workflow | Surface | Endpoint / tool | p50 | p95 |
|---|---|---|---|---|
| List MCP tools | MCP | tools/list | 50 ms | 150 ms |
| Topic search | API/MCP/CLI | driftless_context_search, GET /topics/search | 120 ms | 350 ms |
| Unified retrieve | API/MCP/CLI | context retrieve (F1.5) | 150 ms | 400 ms |
| Topics for files | API/MCP/CLI | driftless_context_get_for_files, GET /topics/match-files | 120 ms | 350 ms |
| Topic get | API/MCP/CLI | driftless_context_get, GET /topics/:slug | 60 ms | 180 ms |
| Project card next | API/MCP/CLI | driftless_project_card action:next | 100 ms | 300 ms |
| Collection records | API/MCP/CLI | driftless_collection_record list | 120 ms | 350 ms |
| Broker operations | API/CLI | GET …/broker/connections/:provider/operations | 250 ms* | 800 ms* |
| Broker invoke | API/CLI | POST …/broker/connections/:provider/invoke | bound by provider | bound by provider |
Payload ceilings (single read response, JSON, uncompressed)
| Read | Default ceiling | Notes |
|---|---|---|
tools/list | 60 KB | compact schemas (F3.1); paginate beyond (F3.2) |
| list/search results page | 40 KB | enforce limit, default view=brief |
single topic (full) | 50 KB | brief view drops content/components |
project card next bundle | 40 KB | bundle resolved by view (F5.5) |
| collection records page | 40 KB | paginate (F6.2) |
| broker records page | 40 KB | hard-cap output size (F7.4) |
gates.md.
Hard backstop (T7): every MCP tool response — static and synthesized —
passes through a byte governor at ToolRegistry.call capped at 50 KB
(DRIFTLESS_MCP_RESPONSE_MAX_BYTES overrides). Under the cap responses are
verbatim; over it the largest lists/strings are shrunk and the response
carries truncated: true + a hint (never a silent cut). The per-read
ceilings above are what well-behaved envelopes should hit; the governor is
the guarantee that an unbounded upstream payload (e.g. a raw provider
operations list) can never flood an agent’s context. Enforced by
apps/mcp/src/tools/response-budget.spec.ts with worst-case fixtures.
Retrieval quality bars
Measured by the ranking eval harness (F1.6) on a labeled query set:- Recall@10 ≥ 0.90 — the right topic is in the top 10 for known queries.
- MRR ≥ 0.70 — the right topic ranks high, not just present.
- No regression vs the current ranking on the labeled set when search moves to indexed full-text (F1.2) and match-files candidate selection is redesigned (F1.3).