compare_documents

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

With no annotations, the description carries the burden for behavioral disclosure. It does well by specifying three concrete result modes: byte identity, revision ancestry via byte-prefix matching, and field-by-field structural diff. It also adds negatives ('Renders nothing and compares no pixels'), which prevents common misconceptions. It does not mention effects, permissions, or edge cases, but this is a read-only comparison tool and the description largely covers its 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?

The description is two tight sentences with no filler. The first sentence frames the purpose and value question, and the second enumerates outcomes succinctly. Every clause earns its place.

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?

Given there is no output schema, the description compensates by naming the three possible result categories (byte identity, revision ancestry, structural diff). The input schema fully covers parameters. It lacks only concrete boolean/response shape details, but an agent can reasonably infer what to expect and when to invoke the tool.

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 description coverage is 100%, so the schema already documents all four parameters well. The description adds modest context by framing one document as trusted ('the original you already hold') and the other as candidate, but it does not need to elaborate on URL/PATH mechanics because the schema already covers them. This matches the baseline for full schema coverage.

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 names a specific verb ('Compare'), a clear resource (candidate document against the original you hold), and the central question ('is this the same file, unchanged?'). It is easily distinguished from sibling tools that inspect, triage, or check redaction.

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?

The description clearly positions this tool as the multi-file comparison tool, saying it answers what 'a single-file check cannot.' It implies when to use it: when an original already exists and an unchanged/revision/diff verdict is needed. It does not explicitly name sibling alternatives or give exclusion conditions, so it stops short of a 5.

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