Timeout/abort error (Claude code)

[stwalsh]

I've been playing with building a Claude Code environment for government guidance content design.

I've been using a little fetcher that it made to grab legislation and turn it into markdown. This is so it can check guidance accuracy against the law.

I thought I'd try integrating lex instead. It worked, but seems to choke on some point at a complex query.

I should say I'm an amateur - a government content designer hoping to make something for the community - so I may be steering Claude to do something stupid. But I asked it to log the problem, and I've pasted it below.

MCP lex Server Testing Log

Date: 2026-01-16
Server: https://lex.lab.i.ai.gov.uk/mcp
Purpose: Testing MCP integration for legislation lookups in GOV.UK editing workflow

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Test Results Summary

Test	Status	Response Time
Health check	✅ Pass	~1-2s
Stats	✅ Pass	~1-2s
Lookup (DPA 2018)	✅ Pass	~1-2s
Search Acts (product safety)	✅ Pass	~1-2s
Get sections (uksi/2024/1332)	✅ Pass	~1-2s
Search explanatory notes	✅ Pass	~1-2s
Search amendments	✅ Pass (empty result)	~1-2s
Search sections (group registration)	✅ Pass	~1-2s
Search sections (holding company)	✅ Pass	~1-2s
Search sections (registration fee)	✅ Pass	~1-2s
Search sections (compliance scheme)	✅ Pass	~1-2s
Search sections (28 days notify)	✅ Pass	~1-2s
Search sections (complex query)	❌ Timeout	AbortError
Get sections (retry)	❌ Timeout	AbortError

Total calls before failure: ~12-13
Published rate limit: 60 requests/min, 1000/hour per IP

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Detailed Test Log

1. Health Check

Tool: mcp__lex__health_check_healthcheck_get
Result:
{
  "status": "healthy",
  "database": "qdrant",
  "collections": 8,
  "collection_details": {
    "caselaw_section": {"points": 4723735, "status": "green"},
    "explanatory_note": {"points": 83527, "status": "green"},
    "legislation_section": {"points": 2096731, "status": "green"},
    "caselaw_summary": {"points": 61107, "status": "green"},
    "embedding_cache": {"points": 238600, "status": "green"},
    "amendment": {"points": 892210, "status": "green"},
    "legislation": {"points": 219685, "status": "green"},
    "caselaw": {"points": 69970, "status": "green"}
  }
}

2. Stats

Tool: mcp__lex__get_live_stats_api_stats_get
Result:
{
  "acts_and_sis": "219,685",
  "provisions": "2,096,731",
  "explanatory_sections": "83,527",
  "amendments": "892,210",
  "pdf_legislation": "94,419",
  "pdf_provisions": "1,086,007",
  "last_updated": "12:45 UTC"
}

3. Lookup Legislation (DPA 2018)

Tool: mcp__lex__lookup_legislation
Params: legislation_type=ukpga, year=2018, number=12
Result: Successfully returned metadata for Data Protection Act 2018
- 1176 provisions
- Status: revised
- Extent: United Kingdom

4. Search Acts (Product Safety)

Tool: mcp__lex__search_for_legislation_acts
Params: query="product safety consumer protection", limit=5, include_text=false
Result: Returned 5 results including:
- General Product Safety Regulations 2005 (uksi/2005/1803)
- General Product Safety Regulations 1994 (uksi/1994/2328)
- EU Directive 2001/95/EC
- Recreational Craft Regulations 2017
- Consumer Safety Act 1978 Commencement Order

5. Get Legislation Sections

Tool: mcp__lex__get_legislation_sections
Params: legislation_id=uksi/2024/1332, limit=5
Result: Successfully returned 5 sections with full text:
- Regulation 2 (Interpretation)
- Schedule 4 (Producer reporting information)
- Regulation 30 (Determination of applications)
- Regulation 48 (Conditions of approval)
- Regulation 58 (Scheme administrator)

6. Search Explanatory Notes

Tool: mcp__lex__search_explanatory_note
Params: query="product safety market surveillance", size=3
Result: Returned 3 explanatory notes including:
- Section 18 interpretation (ukpga/2020/29)
- Schedule 11 construction products (ukpga/2022/30)
- Section 146 construction products (ukpga/2022/30)

7. Search Amendments

Tool: mcp__lex__search_amendments
Params: legislation_id=uksi/2005/1803, size=5
Result: Empty array (no amendments found for GPSR 2005)
Note: May be data gap or genuinely no amendments indexed

8-12. Multiple Section Searches (all successful)

Various searches against uksi/2024/1332 for:

• Group registration / holding company / subsidiary
• UK establishment requirements
• Registration fees
• Compliance scheme exemptions
• 28-day notification requirements

All returned relevant provisions from Schedule 9 (Corporate Groups) and Schedule 1 (Charges).

13. Failed Query

Tool: mcp__lex__search_for_legislation_sections
Params: query="compliance scheme obligation exempt registration reporting recycling not disposal", legislation_id=uksi/2024/1332, size=3
Error: MCP error -32001: AbortError: The operation was aborted.

14. Retry (also failed)

Tool: mcp__lex__get_legislation_sections
Params: legislation_id=uksi/2024/1332, limit=3
Error: MCP error -32001: AbortError: The operation was aborted.

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Error Analysis

The AbortError: The operation was aborted error occurred after ~12-13 successful requests over approximately 10-15 minutes. This is well below the stated rate limits.

Possible causes:

1. Server-side timeout on query processing
2. Network interruption
3. Server load/resource constraints
4. Connection pool exhaustion

Not likely rate limiting because:

• Error message doesn't indicate rate limit (no 429, no "too many requests")
• Request count was ~13, far below 60/min limit
• Simple retry query also failed immediately

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Overall Assessment

The MCP works well when it works:

• Fast responses (~1-2s)
• Good semantic search results
• Clean markdown output
• Explanatory notes very useful
• Section-level retrieval excellent for accuracy checking

Issues:

• Intermittent timeout/abort errors
• No graceful degradation or retry logic apparent
• Empty amendments result for GPSR 2005 (data gap?)

Recommendation: Suitable for production use with fallback to local files or fetch-legislation.js when MCP is unavailable.

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Follow-up Test: Native HTTP Transport

After the initial failures, we tested whether the mcp-remote proxy was the issue by switching to Claude Code's native HTTP transport:

claude mcp add --transport http lex https://lex.lab.i.ai.gov.uk/mcp

Results

Test	Transport	Status
Health check	mcp-remote (npx)	❌ AbortError
Get sections	mcp-remote (npx)	❌ AbortError
Health check	Native HTTP	❌ AbortError
Get sections	Native HTTP	❌ AbortError

Conclusion: Same AbortError: The operation was aborted with both transport methods. This rules out mcp-remote as the cause — the problem is server-side.

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Configuration

.mcp.json:

{
  "mcpServers": {
    "lex": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote@latest",
        "https://lex.lab.i.ai.gov.uk/mcp"
      ]
    }
  }
}

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Log generated by Claude Code during MCP testing session