search_graph/trace_path pagination silently truncates agent answers (measured recall drop 0.72 → 0.52) #1382

Version: eval-97ce23f (v0.9.0+338) · Client: Claude Code · Model: Claude Haiku 4.5
Setting: 300-run benchmark, 2 Java repos (apache/kafka 184k nodes, jackrabbit-oak 132k nodes), warm daemon throughout.

What happens

Graph responses carry total and has_more, and the installed SKILL.md correctly tells the agent:

search_graph results default to 50 per page — check has_more and use offset.

In practice agents frequently do not page, and nothing else in the payload signals that an answer is partial. The result is a confidently-worded but incomplete answer, which is harder to notice than a noisy one.

Measured effect

Task class: "which files declare a method whose shortest call chain to X is exactly 2 calls long". Same agent and model, grep only (A) vs grep + graph (B), 5 repetitions per task:

Precision is essentially identical; recall collapses. The graph arm is not more wrong — it finds less. The grep-only agent over-answers (34 files for a 6.5-file answer) and catches more by sheer volume.

Across all treatment runs, 429 responses carried has_more.

Concrete case

IndexRootDirectory.getIndexesPerPath in jackrabbit-oak; true answer 5 files.

• grep-only agent listed 8 files → found 5 of 5.
• graph agent listed 2 files → found 1 of 5, missing four test files.

The graph had the data: its trace_path(direction="inbound") returned callers_total: 4 correctly, and a later query_graph returned 4 rows. The agent stopped at a partial view and reported it as complete.

Suggestion

Make truncation hard to miss rather than merely reported:

• include the remaining count in the rendered text of the response, not only in a JSON field an agent may skip; or
• return an explicit truncated: true with a short human-readable note; or
• auto-page up to a bounded limit for trace_path, where caller sets are usually small.

Any of these would preserve the token savings the tool is built for while removing the silent-incompleteness failure mode.