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docs: add MCP tool limitations, report_feedback example, and description quality guidelines#112

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improve/mcp-tool-descriptions
Mar 31, 2026
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docs: add MCP tool limitations, report_feedback example, and description quality guidelines#112
firstdata-dev merged 7 commits intomainfrom
improve/mcp-tool-descriptions

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What this PR does

Adds comprehensive Limitations documentation for all 5 MCP tools based on verified testing and schema analysis. Also adds the missing Example for report_feedback (the only tool without one) and establishes a 6-dimension description quality checklist for future tool additions.

Background: MCP Search Quality Research #5 found 97.1% of MCP tool descriptions contain at least one 'smell'. FirstData scored well on Purpose/Guidelines/Examples but had a systematic gap in Limitations (0.5/5). This PR fixes that.

Changes

SKILL.md — MCP Tools Reference (new section)

  • Common Limitations: authentication, daily quota, network dependency
  • search_source: 200 max results, keyword substring matching, ⚠️ space-in-keyword pitfall, domain substring matching, no boolean operators
  • get_source: silent error behavior (isError:false with error objects), recommended batch size ≤20
  • ask_agent: query constraints, non-idempotent, 2-8s response time, web_search trigger warning
  • get_access_guide: incomplete instruction coverage, 3-20s variable response time, operation specificity
  • report_feedback: message length, non-idempotent + two usage examples (broken link + outdated content)

Description Quality Guidelines (new section)

  • Core principle: 'Write it right before writing it all' — Functionality (+11.6%) matters ~8× more than Conciseness (+1.5%)
  • 6-dimension PR review checklist

mcp-tool-descriptions-draft.md (new file)

  • Server-side description text, ready to paste into Python code after review
  • Complete verification evidence table

Verification Evidence

Every limitation is backed by schema analysis or live API testing:

Limitation Source
search_source limit: 1–200 inputSchema maximum: 200
Keywords not auto-tokenized Tested: ["中国 GDP"] → 0 results; ["中国", "GDP"] → 173 results
Substring matching Tested: ["中国GDP"] → 1 result; ["GDP"] → 100 results
domain substring matching inputSchema description: "领域关键词,子串匹配"
get_source silent error Tested: invalid ID → {"error":"Not found"} with isError: false
ask_agent response time 3 runs: 7.4s, 2.9s, 1.8s
get_access_guide response time 3 runs: 3.0s, 17.6s, 19.1s
Token quota system TokenVerifyResponse schema: quota_allowed, remaining_daily
Trial quota 30/day /api/trial/session-info: total_calls: 30

6-Dimension Self-Assessment (post-change)

Dimension search_source get_source ask_agent get_access_guide report_feedback
Purpose
Guidelines
Examples ✅ (NEW)
Limitations ✅ (NEW) ✅ (NEW) ✅ (NEW) ✅ (NEW) ✅ (NEW)
Parameters
Return Format

Target: 30/30 ✅

Deployment Note

This PR updates documentation only (SKILL.md). The server-side MCP tool descriptions need a separate deployment — the exact text is provided in mcp-tool-descriptions-draft.md for copy-paste into server code after review approval.

Refs: arXiv 2602.14878, arXiv 2602.18914

…ion quality guidelines

## What this PR does

Adds comprehensive Limitations documentation for all 5 MCP tools based on
verified testing and schema analysis. Also adds the missing Example for
report_feedback (the only tool without one) and establishes a 6-dimension
description quality checklist for future tool additions.

## Changes

### SKILL.md — MCP Tools Reference (new section)
- Common Limitations: authentication, daily quota, network dependency
- search_source: 200 max results, keyword substring matching behavior,
  space-in-keyword pitfall, domain substring matching, no boolean operators
- get_source: silent error behavior (isError:false with error objects),
  recommended batch size
- ask_agent: query constraints, non-idempotent, 2-8s response time,
  web_search trigger warning
- get_access_guide: incomplete instruction coverage, 3-20s response time,
  operation specificity requirement
- report_feedback: message length, non-idempotent, two usage examples
  (broken link + outdated content)

### Description Quality Guidelines (new section)
- Core principle: 'Write it right before writing it all'
- 6-dimension checklist for PR review

### mcp-tool-descriptions-draft.md (new file)
- Server-side description text ready to paste into Python code
- Verification evidence table with test results and schema references

## Verification Evidence

Every limitation is backed by schema analysis or live testing:
- search_source limit 200: inputSchema maximum:200
- Keywords not auto-tokenized: tested ['中国 GDP']→0, ['中国','GDP']→173
- get_source silent error: tested invalid ID returns error object, isError:false
- ask_agent timing: 3 runs measured 1.8s, 2.9s, 7.4s
- get_access_guide timing: 3 runs measured 3.0s, 17.6s, 19.1s
- Token quota: TokenVerifyResponse schema has quota_allowed/remaining_daily
- Trial quota 30/day: verified via /api/trial/session-info

## 6-Dimension Self-Assessment (post-change)

| Dimension | search_source | get_source | ask_agent | get_access_guide | report_feedback |
|-----------|:---:|:---:|:---:|:---:|:---:|
| Purpose | ✅ | ✅ | ✅ | ✅ | ✅ |
| Guidelines | ✅ | ✅ | ✅ | ✅ | ✅ |
| Examples | ✅ | ✅ | ✅ | ✅ | ✅ (NEW) |
| Limitations | ✅ (NEW) | ✅ (NEW) | ✅ (NEW) | ✅ (NEW) | ✅ (NEW) |
| Parameters | ✅ | ✅ | ✅ | ✅ | ✅ |
| Return Format | ✅ | ✅ | ✅ | ✅ | ✅ |

Target: 5/5 tools × 6/6 dimensions = 30/30 ✅

Refs: MCP Search Quality Research #5, arXiv 2602.14878, arXiv 2602.18914
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@mingcha-dev mingcha-dev left a comment

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mingcha QA - PR #112: MCP tool limitations documentation + report_feedback example + description quality guidelines. No sensitive words. Content quality high — especially the search_source keyword tokenization warning (Issue #93 related). LGTM

Address review feedback:
1. Keyword space behavior: reworded from restrictive ('NOT auto-tokenized')
   to guiding ('pass each term as a separate array element'), with 'New Zealand'
   design rationale per 明鉴's suggestion
2. Token quota: added explicit note that no client-facing API exists to query
   remaining quota at runtime, per 明鉴's question
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✅ LGTM. MCP 工具文档质量提升——5 个工具全部补充 Limitations,report_feedback 补了 Example,6 维度自评 30/30。

基于真实测试数据(schema 分析 + API 调用验证),文档质量很扎实。建议合并。

Draft had shortened versions of the examples; now both files have
identical text as required by the draft file's own header.
1. Examples: unified to short version per review (server-side descriptions
   should be concise)
2. Quota: replaced 'no client-facing API' with actual mechanism —
   Token verification API (POST /api/token/verify) returns remaining_daily,
   but this is a separate HTTP call, not available via MCP tool invocation
Critical fix:
- Multiple keywords use OR logic, NOT AND. Verified:
  GDP=100, health=78, GDP+health=138 (>max → OR)
  trade=123, agriculture=45, trade+agriculture=131 (>max → OR)
- Draft header: 'must remain identical' → 'condensed from SKILL.md,
  semantics must match'
- Added OR logic verification to evidence table
Per 明鉴 review: Agent needs response time info for all tools,
not just the slow ones, to make informed tool selection decisions.
@firstdata-dev firstdata-dev merged commit 651c648 into main Mar 31, 2026
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