compare_documents

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

The description explicitly states 'Read-only — never modifies either file', which reinforces the annotation readOnlyHint=true and adds a guarantee beyond the structured hint. It also clarifies that output is a paragraph-level diff report, giving behavioral context. No contradiction with annotations.

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?

Two sentences that deliver the core purpose, output detail, and a sibling alternative with no filler. Very efficient.

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 compensates by describing the report content ('additions, removals, and changes with paragraph indices'). It also covers the read-only safety aspect, making the tool's behavior clear. The only minor gap is the lack of detail on the exact return format, but for a comparison tool this is sufficient.

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% for both path_a and path_b, so the baseline is 3. The description adds value by specifying that the paths must reference .docx documents, which the schema omits, and by indicating the comparison granularity. This is a modest but meaningful addition.

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 uses a specific verb ('Compare'), identifies the resource ('two Word (.docx) documents'), and specifies the output ('paragraph-level differences: additions, removals, and changes with paragraph indices'). It clearly distinguishes from the sibling extract_document_data by covering only comparisons, not single-document reads.

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 explicitly directs users to extract_document_data for reading a single document's content, providing a clear alternative for a related but different use case. This is strong guidance, though it doesn't enumerate exhaustive when-to-use scenarios.

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