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

Annotations already declare this is a non-read-only, non-destructive, closed-world mutation, so the safety bar is partly covered. The description adds real behavioral detail beyond that: for a navbar link it sets the page target so href and active state stay in sync, whereas for a plain link or button it sets href to the page's ./slug.html. It does not say what happens on an invalid targetPath or missing page, so it is not a 5.

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?

Three sentences, front-loaded with the core action, then parameter sourcing, then the when-to-use trigger. Dense but every sentence contributes; only the UI-picker aside is arguably decorative.

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 two-parameter mutation with no output schema and annotations covering the safety profile, the description supplies the prerequisite, parameter provenance, and the divergent behavior for navbar vs plain link/button. Error behavior and return value are unstated, which is the only remaining 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 schema already defines both parameters, including 'Page id or name' and the zero-based index array from read_page. The description reinforces the read_page provenance and maps each parameter to its effect, but adds no syntax or format detail the schema lacks. Baseline 3 is correct when the schema carries the load.

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+resource: 'Point an existing link at a project page', with the UI analogue ('Link to' picker) anchoring what it does. It is clearly distinguished from siblings like create_page, update_page, and read_page, which are referenced as different steps in the workflow rather than as competing tools.

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?

Explicitly states the triggering workflow: 'Use after create_page to wire a navbar to the new page', which is genuine when-to-use guidance. It does not state exclusions or name a competing tool for the same job, so it stops short of a 5.

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