What changed inside the file

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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds substantial behavioral context beyond those: per-module/Power Query granularity, unified diff format, the fact that worksheet cell values are not compared, the default revision of HEAD, and the binary-file rationale. This is exactly the kind of added context the rubric rewards.

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 six sentences, each earning its place: core action, motivation, usage timing, a key limitation, default behavior, and requirement. It is front-loaded with the primary function and contains no redundant or filler content.

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 read-only comparison tool with a full parameter schema and an output schema, the description covers all operational essentials: what is compared, what is not compared, revision semantics, and repository prerequisites. An agent has enough information to decide whether and when to call it.

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 baseline is 3. The description does mention the revision default and that any git revision is accepted, but this is already in the schema. It does not add significant parameter-level meaning beyond what the schema provides.

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 states a specific verb and resource: 'Lists what changed inside an Office file since a git revision, one entry per VBA module and Power Query, with a unified diff.' This is precise and differentiates it from ordinary git diff, which the description explicitly says cannot handle the binary file format. No sibling tool has a similar focus.

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?

It provides explicit usage timing: 'Call this before committing, and to review what an agent or a colleague changed.' It also explains why git diff is not an alternative and states the prerequisite that the file must be inside a git repository and tracked, giving an agent clear conditions for invocation.

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