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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is fully covered. The description adds the useful scope fact that only public documentation is reachable, but says nothing about the shape or size of the returned content.

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 short sentences, front-loaded with the action and followed by the key limitation. Nothing is wasted or repeated from the structured fields.

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 one-enum-parameter read tool with full annotations and no output schema, this covers what it reads and what it cannot read. Only the difference in content between the two document options is left unstated.

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 coverage is 0%, yet the single enum parameter is effectively explained: "documentation" maps to docs and "agent guide" maps to agent-guide. It does not say what distinguishes the two documents' content, which is the only remaining semantic gap.

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?

Specific verb ("Read") plus a concrete resource ("public Headron documentation or its agent guide"), and it states a scope boundary ("cannot inspect a local project"). Sibling plan_change is plainly a different operation, so the agent can tell them apart, though no sibling is named.

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 negative constraint "cannot inspect a local project" usefully steers the agent away from a wrong expectation, but there is no positive when-to-use guidance and no explanation of when to pick the agent-guide versus the docs value.

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