pbix_diff

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

No annotations are provided, so the description carries the full transparency burden. It explicitly states 'read-only,' which is a key safety trait, and lists the categories of differences it reports, including per-input-type exclusions. It does not disclose output structure or error behavior, but for a read-only diff tool this is reasonably transparent.

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 a single, well-organized sentence with a leading clause, a list of diff categories, and a concluding metaphor. It is compact and front-loaded with the core purpose. The parentheticals add necessary precision without excessive verbosity.

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?

For a tool with only two parameters and no output schema, the description covers the key aspects: inputs, output categories, and per-input limitations. It lacks explicit guidance on mixed input types and return format, but these are not critical for a read-only diff utility. Overall, it is complete enough for an agent to invoke correctly.

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?

The input schema already provides 100% coverage with clear descriptions for both pathA and pathB. The description adds semantic value by clarifying that both paths must be the same kind (both .pbix or both trees) and that trees refer to the output of unpack_to_source, which is not evident from the schema alone.

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 clearly states the tool performs a 'semantic diff' between two .pbix files or unpacked source trees, and enumerates exactly what differences are detected (files, TMDL tables+measures, report pages+visual counts, M queries). It distinguishes itself from siblings by framing it as 'The semantic git diff for client models' and emphasizing read-only behavior.

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 specifies valid input combinations (both .pbix or both unpacked trees), references the source tree format from unpack_to_source, and notes scope limitations (TMDL only for trees, M queries only for .pbix). It does not explicitly name alternative diff tools but provides adequate context for when to use it.

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