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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: scoping to identifier types (anonymous IP, BYO key hash, account ID) and the omit-key-to-list behavior. No contradictions 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?

Four compact sentences, each earning its place: core action, usage example, scoping, and sibling pairing. The description is front-loaded with the primary behavior and contains no filler or redundancy.

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 read-only tool with no output schema, the description covers the return behavior (value or list of keys), the intended use case, the scope, and related tools. No important gaps remain.

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?

The schema already documents the sole 'key' parameter and explains that omitting it lists all keys (100% schema coverage). The description adds semantic value by giving example key types ('user's target ticker, an address, prior research notes') and noting that saved values come from remember, helping the agent compose meaningful key arguments.

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 opens with 'Retrieve a value previously saved via remember, or list all saved keys,' naming a specific action and resource, and clearly distinguishes the dual behavior of fetching vs listing. It also explicitly references sibling tools (remember, forget), making its purpose unambiguous within the tool family.

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 gives concrete usage context ('Use to look up context the agent stored earlier... without re-deriving it from scratch'), explains the scope ('Scoped to your identifier'), and explicitly names alternatives: 'Pair with remember to save, forget to delete.' This clearly tells the agent when to use recall versus related tools.

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