why_file

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden, and it does disclose useful semantics: the span of sources covered (local Claude Code, Codex, DeepSeek Harness, Pi, ThoughtDAG) and the epistemic caveat that '≈' is a candidate explanation, not a verified reason. It does not disclose read-only vs mutating behavior, auth requirements, result ordering, or volume/pagination behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single dense clause with no filler; each element (when, Δ, asked, answer, deep link) earns its place. It is slightly awkward to parse because it is a fragment with symbolic notation (Δ, ≈) and no leading verb, which costs a bit of front-loading.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description responsibly sketches the return contents (timing, change, prompt, candidate explanation, deep link). Missing for a 3-param tool with zero annotations are the mutation/safety profile and any hint about result volume or the meaning of the defaulted `limit`.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 67%: limit and include_read are self-documented in the schema, while the required `path` has no description. The description partially compensates by revealing that the target can be a 'file, URL or paper', which is non-obvious from the parameter name `path`. That is real added meaning, but it does not cover the remaining ambiguity.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description is a noun phrase describing the payload ('The turns ... that touched a file, URL or paper') rather than a verb-led statement of what the tool does. The intended action (find/list turns that touched an artifact, with explanation) is inferable but never stated outright, and there is no differentiation from siblings like recall_turn or why_check.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no when-to-use guidance, no statement of prerequisites, and no mention of how this differs from find, recall_turn, or why_check. The agent must guess the routing among four siblings purely from their names.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.