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

Annotations already cover read-only, destructive, and idempotency hints. The description adds useful behavioral context: it requires an existing project location and returns 404 if the slug is not found. It does not explain whether an existing review location is replaced, but the idempotentHint mitigates that gap.

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 short and front-loaded with the core action, followed by the key error behavior. There is a minor redundant title line, but overall every substantive sentence earns its place.

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 simple two-parameter tool with an output schema and informative annotations, the description provides the core operation, the lookup mechanism, and the main failure mode. It omits what happens when the review id is not found, but this is not a major gap given the schema and output schema.

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 description coverage is 100%, so both parameters are already documented with meaningful detail. The description's 'by slug' phrasing adds no significant meaning beyond the schema's 'Slug of an existing project location' and its 404 note. 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?

The description uses a specific verb ('Assign') and resource ('existing project location to a review by slug'), clearly distinguishing this from siblings like updateLocation or updateReviewSource. It also adds the 404 behavior for a missing location slug, reinforcing what the tool targets.

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?

There is no guidance about when to use this tool versus alternatives such as updateLocation, updateReviewSource, or other review update tools. The purpose is implied, but the agent is left to infer the selection criteria from the name and description.

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