MCP query_dataset with an empty selection.measures reaches the SQL driver and answers 500 DATABASE_ERROR, while the REST twin refuses it 400

qa#3 · os-tesla · session_01L9qibw6yXcLi9aRRBpPT4W

Reproduction (stock showcase at `ee9ad83`, keyed MCP session over /api/v1/mcp with an admin osk_ key; reproduced twice)

tools/call query_dataset {datasetName:"showcase_invoice_metrics", selection:{measures:[]}} → isError {error:{code:"DATABASE_ERROR", status:500, message:"The database refused to run a raw statement…"}}. Server log: [sql-driver] DATABASE_ERROR … SQLITE_ERROR … near "FROM": syntax error.
With measures:[] and dimensions:["status"], the tool serves group rows that have no measures.
REST twin: POST /api/v1/analytics/dataset/query with the same selection → 400 VALIDATION_FAILED "body.selection.measures must be a non-empty array of measure names."

Expected: the MCP door refuses the empty measure list before dispatch, with the same answer as the REST door; never a 500.

Mechanism

The MCP input takes DatasetSelectionSchema by reference (packages/spec/src/api/analytics.zod.ts:633, measures: shared.measures), and that schema accepts an empty list. The REST route adds its own non-empty check (packages/rest/src/analytics-routes.ts:489), which the MCP door lacks. The executor therefore builds a SELECT with no projection.

Fix direction: put the non-empty rule in the shared selection schema, or give the MCP input the same guard, and pin it in packages/mcp/src/mcp-dataset-tools.test.ts.

QA-source: #33025 · ai.mcp-dataset-tools · observed beside the clauses

triage#1 · hotlong · session_01Q4EjjMnyLqJdzuktEmRPXH

Path: none

Triage: first touch → `domain:server` · p2 · `pm:queue` · 2026-11-13T05:48Z

⛔ Not a claim.

Line: an agent over MCP query_dataset with an empty selection.measures · any dataset · every such call · measured twice.
Grade: p2. The tool reaches the SQL driver and answers 500 DATABASE_ERROR with raw driver text, where the REST twin answers 400 VALIDATION_FAILED. It is a loud failure and the agent corrects it by passing a measure, so it is not a wrong answer or a stuck agent, and the MCP raise does not apply. The validation gap and the leaked driver text are the fix. It is linked under the MCP epic [Epic] MCP: what an agent can read and write on the HTTP MCP door, and answers that agree with the gate #32897.

Generated by Claude Code

domain:server#7 · os-tesla · session_01L9qibzuZJBQY4wUQFJbkfx

Claim: PM loop round 3, card thread · 2026-11-13T15:53Z · MCP p2 under the maintainer's 「mcp 相关 p2 任务也可以派发处理」 (2026-11-13T15:50:52Z)
Session: session_01L9qibvxW3CnsR8FmFCXFQn
Account: os-tesla
Branch: claude/project-thread-mbqhe2
Worktree: objectstack-issue-33028
Domain: domain:server
Seat: domain:server#7
File surface: packages/mcp/src/mcp-http-tools.ts (the query_dataset input check) or the dataset tool module it delegates to, packages/rest/src/analytics-routes.ts only to export and share the existing non-empty check, their tests, one root changeset. ⛔ No packages/spec change. Stop on breach.
Container & model: S, mode:thread, model: default (dispatch-gates --tier: no path-derived mandate; PM default), effort: medium
Clause-②: no (narrowing) — an empty measure list that answered 500 at the MCP door is refused 400 like the REST door
Metadata-protocol: none
Responsibility: the 500 comes from the MCP query_dataset door in packages/mcp (objectstack) | the REST route's guard already covers its own door | any MCP agent sending an empty measure list reaches it today
Thread-read: 6845330955
Premise: holds (reproduced twice by qa#3 at ee9ad834; the dev reproduces at origin/main first)
Serial constraints cleared: mcp-http-tools.ts is shared with #32442 (server#5) and this seat's #32872, #32686 (PR #33123), #33107: edits stay on the query_dataset path; land serially, merge main after a sibling lands

domain:server#7 · os-tesla · session_01L9qibzuZJBQY4wUQFJbkfx

Claim amendment to this seat's claim 6857989541 on #33028 · 2026-11-13T15:55Z: the file surface adds

packages/qa/dogfood/test/dataset-package-scoped-readers.dogfood.test.ts: one case sends measures: [] to POST /api/v1/analytics/dataset/query and to MCP query_dataset as one caller, and asserts the same code, status and message (the agreement pin, following the house precedent of serving both doors side by side);
packages/services/service-analytics/src/dataset-tools.ts (queryDataset) and its test, IF the guard can sit at that shared executor. The executor also serves the product-AI chat tool query_dataset, which lacks the same guard (same defect class, same seam, unclaimed). One guard there covers both faces.
packages/rest/src/analytics-routes.ts is dropped from the surface: the two packages share no dependency, so there is nothing to export.

domain:server#7 · os-tesla · session_01L9qibvxW3CnsR8FmFCXFQn

os-dev-report

{
  "issue": 33028,
  "status": "done",
  "branch": "claude/project-thread-mbqhe2",
  "pr": "https://github.com/objectstack-ai/objectstack/pull/33141",
  "session": "session_01L9qibvxW3CnsR8FmFCXFQn",
  "premise_still_valid": true,
  "summary": "query_dataset now refuses a selection with measures: [] (with or without dimensions) 400 VALIDATION_FAILED with the REST door's sentence ('body.selection.measures must be a non-empty array of measure names.'), before the dataset is read. Per the seat's ruling and claim amendment 6858058804 the guard sits in the shared service-analytics executor (dataset-tools.ts queryDataset), so it covers the MCP tool and the product-AI chat tool (execute) in one place; the MCP door relays the thrown code/status/message whole (thrownRefusalEnvelope), so packages/mcp is unchanged. packages/rest and packages/spec are untouched. The REST/MCP agreement is pinned by one dogfood case per selection shape, since rest and service-analytics/mcp share no runtime dependency.",
  "tests": "Measure at 7c36f524: new dataset-tools.test.ts pins 2 failed | 26 passed (28), both measures: [] cases SERVED (answer object, rowCount 1). At 4beb312f: dataset-tools.test.ts 28/28; service-analytics test 215 files, 5187 passed | 332 skipped; typecheck exit 0 (--listFiles includes the test); dataset-package-scoped-readers.dogfood.test.ts 18/18. Ablation A1 (source, ablation-replace anchor 'if (raw.selection.measures.length === 0) throw' -> 'if (false) throw', blob 788afd5b -> c09a6df0): unit 2 failed | 26 passed; restored blob == HEAD, git diff HEAD empty. Ablation A2 (dist, replacement '... === -7) throw', blob -> befa3942, service-analytics rebuilt, ablation-dist-preflight exit 0): dogfood file 2 failed | 16 passed, MCP answered DATABASE_ERROR (sql-driver 'near \"FROM\": syntax error') without dimensions and isError false with dimensions, the card's two observations; restored, rebuilt, preflight --absent exit 0.",
  "gates": "dispatch-gates --commands at 4beb312f: 66 families, record /mnt/project-files/server-seat-7/r2026-11-13/out/33028-gates-ran-4beb312f.list; --ran: 66 accounted, 65 run, 1 NOT MEASURED (check:dual-build-cjs-loads exit 3 PREREQUISITE NOT MET, dist of packages outside the closure; self-test 93 cases passed). check-plugin-teardown-shape --self-test first exit 3 (shallow), after fetching 621a4876 exit 0. pnpm lint exit 0. CI check-runs: in_progress at report time.",
  "dogfood_battery": "4beb312f · os-verify-lock VERDICT command-exit 0 · Test Files 460 passed | 3 skipped (463) · Tests 3876 passed | 42 skipped (3918) · no failures",
  "mcp_calls": "4 — reads only: issue_read get x1, issue_read get_comments x2, pull_request_read get x1 (PR body precedent); 0 write tools",
  "api_writes": "2 — relay pr_create (POST pulls + assignees os-tesla) via fleet-write dispatch run 43471347448; this os-dev-report comment via post-stamped. Plus git push (not a REST write).",
  "open_questions": [],
  "security_findings": "none",
  "out_of_scope_findings": [
    "Other doors to the executor's empty projection (order step 3): REST single + batch go through answerDatasetQuery, which already refuses; MCP query_dataset and the chat tool query_dataset go through dataset-tools.ts, both fixed here. No other caller passes a caller selection to AnalyticsService.queryDataset. carrier: none",
    "Wording: the tools now answer 'body.selection.measures ...' (the REST sentence, by the parity rule) although a tool input has no body; rewording means changing both doors together. carrier: none, noted in Acceptance notes"
  ]
}

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MCP query_dataset with an empty selection.measures reaches the SQL driver and answers 500 DATABASE_ERROR, while the REST twin refuses it 400 #33028

Reproduction (stock showcase at `ee9ad83`, keyed MCP session over /api/v1/mcp with an admin osk_ key; reproduced twice)

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Triage: first touch → `domain:server` · p2 · `pm:queue` · 2026-11-13T05:48Z

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MCP query_dataset with an empty selection.measures reaches the SQL driver and answers 500 DATABASE_ERROR, while the REST twin refuses it 400 #33028

Description

Reproduction (stock showcase at ee9ad83, keyed MCP session over /api/v1/mcp with an admin osk_ key; reproduced twice)

Mechanism

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objectstack-fleet commented on Nov 13, 2026

Triage: first touch → domain:server · p2 · pm:queue · 2026-11-13T05:48Z

objectstack-fleet commented on Nov 13, 2026

objectstack-fleet commented on Nov 13, 2026

objectstack-fleet commented on Nov 13, 2026

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Reproduction (stock showcase at `ee9ad83`, keyed MCP session over /api/v1/mcp with an admin osk_ key; reproduced twice)

Triage: first touch → `domain:server` · p2 · `pm:queue` · 2026-11-13T05:48Z