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

Annotations only declare readOnlyHint/idempotentHint; the description adds that no MCP Token, model call, or credit charge is involved, that authenticated scopes are excluded, and that responses carry scope, accountAuthorization=not_evaluated, action, and either list or item. Those auth and cost disclosures go meaningfully beyond the structured 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?

Dense and front-loaded: cost/auth exemption first, then the search/get distinction, then scope limits, then return shape and exclusions. Some return-field detail duplicates the output schema, which is mild redundancy, but no sentence is wasted.

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?

Given an output schema exists, the description need not spell out return fields, yet it does so briefly while still covering auth, cost, scope restrictions, and the search/get split. Nothing essential for correct invocation is missing; only the non-scope filters go undescribed.

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%, so the baseline is 3. The description still adds value by clarifying the omission-or-recommended constraint on scope, the id linkage to search results, and how action drives list vs item output. It doesn't document pagination or filter params (tags, group, category, keyword), so it stops short of a 5.

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+resource (read public prompts) with two named modes, search (default) and get, and defines exactly what search returns (published, reviewed system recommendations) versus get (one public detail by id). An agent can distinguish this read-only prompt library from mutation-oriented siblings like generate_image or reverse_prompt without opening the schema.

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 search is the default, that get requires an id returned from search, that scope must be omitted or set to recommended, and that mine/favorites/private remain authenticated and out of scope. It also names what the tool will never do (generate, sync, evaluate, rewrite), which is a clear when-not-to-use boundary.

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