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

Annotations only declare readOnlyHint=false and openWorldHint=false, so the description carries the real disclosure burden and does so well: needs sign-in (auth requirement), re-posting replaces the existing review (upsert/overwrite semantics), and the output carries a 'via an assistant' label. These are exactly the traits an agent cannot infer from the schema or 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 short sentences, each delivering distinct information: identity/scope, content-provenance rule, labeling and idempotency, and auth. Front-loaded with the action, and no sentence is redundant with 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 write tool with no output schema and only partial annotations, the description covers the critical unknowns: auth, overwrite behavior, labeling, and content policy. It omits error/failure behavior and the 50-character minimum on review text, which is a minor residual gap rather than a blocker.

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 75%, so most parameters are already documented. The description reinforces the 'review' parameter by requiring it to be the person's own words, but adds nothing about media_type (ambiguous-name narrowing) or contains_spoilers, which are only covered in the schema. Baseline-adequate, not additive.

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 first sentence states a specific verb and resource (post a review of a title) and scopes it to the signed-in person's own review. That is clearly separable from sibling rate_title (rating, not text) and add_to_library (saving, not publishing). No ambiguity about what gets created.

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?

It gives explicit behavioral rules for use: the review must be the person's own words, the agent must ask for it rather than write it, and one review per title with re-posting replacing the prior one. It stops short of naming an alternative tool (e.g. rate_title) or when-not-to-post, so it is strong but not fully comparative.

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