Both the MCP server and WebResearcher defaulted to
claude-sonnet-4-5-20250514, which 404s against the Anthropic API.
Update both defaults to claude-sonnet-4-6, which is current as of
2026-04.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The synthesis step was passing max_tokens=4096 to Claude, which was
not enough for a full ResearchResult JSON over a real evidence set
(28 sources). The model's output got cut mid-string, json.loads
failed, and the agent fell back to a stub answer with zero citations.
The trace logger then truncated the raw_response to 1000 chars before
recording it, hiding the actual reason for the parse failure (the
truncated JSON suffix) and making the bug invisible from traces.
Fixes:
- Bump synthesis max_tokens to 16384
- Capture and log Claude's stop_reason on synthesis_error so future
truncation cases are diagnosable from the trace alone
- Log the parser exception text alongside the raw_response
- Stop slicing raw_response — record the full string
Verified end-to-end against the Utah crops question:
- Before: 0 citations, confidence 0.10, fallback stub
- After: 9 citations, confidence 0.88, real synthesized answer
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
New field on ResearchResult: open_questions — follow-up questions that
emerged from the research itself. Distinct from gaps (backward: what
failed) and discovery_events (sideways: what's lateral). Open questions
look forward: 'based on what I found, this needs deeper investigation.'
- OpenQuestion model: question, context, priority (high/medium/low),
source_locator
- Updated agent synthesis prompt to produce open_questions
- Updated agent result builder to parse open_questions from JSON
- 3 new tests for OpenQuestion model
- Updated existing tests for new field
77 tests passing.
Refs: archeious/marchwarden#1
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
WebResearcher — the core agentic research loop:
- Tool-use loop: Claude decides when to search (Tavily) and fetch (httpx)
- Budget enforcement: stops at max_iterations or token_budget
- Synthesis step: separate LLM call produces structured ResearchResult JSON
- Fallback: valid ResearchResult even when synthesis JSON is unparseable
- Full trace logging at every step (start, search, fetch, synthesis, complete)
- Populates all contract fields: raw_excerpt, categorized gaps,
discovery_events, confidence_factors, cost_metadata with model_id
9 tests: complete research loop, budget exhaustion, synthesis failure
fallback, trace file creation, fetch_url tool integration, search
result formatting.
Refs: archeious/marchwarden#1
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
