What is already in the Unreleased changelog?

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

Annotations already provide readOnlyHint and idempotentHint, but the description adds valuable behavior beyond those tags: the section modes return different shapes (parsed pending entries vs raw file), and it discloses the hook-managed state of the changelog so the agent understands why hand-editing is unsafe. No contradiction with annotations.

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?

Four tightly written sentences with no filler: core action first, then when to use it, then the parameter behavior, then the read-only caveat. Each sentence adds distinct information that is not available from the schema or annotations.

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 single-optional-parameter read tool with an output schema, the description covers all decision-relevant context: when to call it, which section value to request, and why it must not be used for writing. Given the large sibling set, the explicit usage triggers and write-route pointer are sufficient to select and invoke this tool 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 schema defines only a single `section` string with a default and has 0% description coverage, so the description carries the entire semantic burden. It fully explains the meaningful values ('unreleased' and 'full') and what each returns, which is precisely the missing information an agent needs.

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 an explicit action—'Read the changelog'—and identifies the resource and scope: the Unreleased changelog, with parsed pending entries by default or the raw file in full mode. It also differentiates itself from write workflows by explicitly saying it is read-only, which helps distinguish it from bump and write-oriented siblings.

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?

Gives concrete triggers: use before adding an entry to avoid duplication, and before a bump to see what will be promoted. It also tells the agent when not to use it by directing writes to the CLI/hook workflow and warning against hand-editing the [Unreleased] section while that hook is active.

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