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

No annotations are provided, so the description must fully disclose behavioral traits. It explains that the tool compares configs and returns changes with old/new values. However, it does not explicitly state that the tool is read-only or mention any authentication requirements or rate limits. The description is adequate but not exhaustive.

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 sentences long, front-loaded with the purpose, and contains zero wasted words. Every sentence adds necessary context.

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 the tool has 3 parameters, no output schema, and no annotations, the description covers the core functionality and parameter usage with an example. However, it does not explicitly describe the structure of the return value, though the phrase 'field paths with old/new values' gives a reasonable expectation.

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 has 100% coverage for all 3 parameters, but the description adds value by explaining the format of 'a' and 'b' (revision_id or branch:draft) and providing a concrete usage example. This goes beyond the schema's descriptions, which only say 'Left side: a revision_id, or...'.

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 compares two agent configs and shows changes section by section with field paths and old/new values. It uniquely identifies this tool among siblings, as no other sibling tool performs diff operations on configs.

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 provides clear context for when to use the tool, including an example of diffing a branch's draft against live head to preview a publish. It does not explicitly state when not to use it, but the context is sufficient and no sibling tool offers similar functionality.

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