Read AGENTS.md

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds only the justification for the tool's existence and the output granularity; it says nothing about behavior when a heading doesn't match, since the case-insensitive prefix match detail lives in the schema.

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, front-loaded with the primary action and output modes. The trailing clause about what a client would otherwise have to look for is rationale rather than instruction, so it is mildly expendable but not harmful.

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 zero-required-parameter read tool with annotations covering safety and no output schema, the description sufficiently conveys what is returned (whole file or a named section). Missing only edge-case behavior when no section matches, which is a minor gap.

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 100% and the single parameter is fully documented there, including the case-insensitive prefix-match semantics. The description only restates the same whole-file-vs-section choice, adding no syntax or format detail beyond the schema. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Return this project's AGENTS.md') plus the two output modes (whole file or one section by heading). This clearly separates it from the sibling write tool author_agents_md and from list_agents_md_sections, which only lists headings.

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 phrase 'the whole file, or one section by heading' implies when to use the section parameter, but the description gives no explicit guidance such as 'use list_agents_md_sections first to discover headings' or any exclusion. Usage is inferable but not stated.

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