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

Annotations already declare readOnlyHint true, openWorldHint false, and idempotentHint true. The description adds valuable context beyond these: it notes the tool is 'readable on every plan state including expired' and explains the deliberate design for payment decisions. It also clarifies the token scoping ('cannot see anyone else's') and the meaning of `matching` when false. 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?

The description is front-loaded with the purpose, then provides usage scenarios, return format, and a note about plan states. It is somewhat verbose for a zero-param tool, but each sentence adds value (e.g., the deliberate design rationale). It could be tightened, but it remains readable and structured.

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?

The description fully explains what the tool returns (`searches` with `saved` slug, `name`, `matching`, `prefilter`, `created_at`), how it behaves on lapsed plans, and the security boundary. Since an output schema exists, the return format is already documented, and the description adds the semantic meaning (e.g., `matching: false` means paused, not deleted). Nothing an agent needs to correctly call this tool is missing.

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?

There are zero parameters, so baseline is 4. The description explicitly states 'Takes no arguments' which is redundant but reinforces the fact. It also explains the output fields, which helps understand the tool's behavior even though no parameters exist. No additional parameter descriptions are needed.

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 states a specific verb and resource: 'Every search saved against this token' and 'list' is implied. It clearly distinguishes from siblings by specifying it lists saved searches with matching status, while other tools like delete_saved_search or save_search perform different actions. The first sentence gives a precise scope.

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?

The description explicitly lists three use cases: 'Call it to find the slug delete_saved_search needs, to check that a search you saved is actually running, or to see what you had before deciding whether to pay again.' This gives clear when-to-use guidance and references a sibling tool, though it does not explicitly say when not to use it. The context is strong enough to qualify as explicit usage direction.

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