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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds valuable behavioral context: it is scoped to the caller's identifier (anonymous IP, BYO key hash, or account ID), and omitting the key returns a list of all keys. This goes beyond the annotations without contradicting them, though it doesn't specify the return format for a missing key, which slightly drops the score.

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 two sentences long and front-loaded with the primary action. Every clause adds value: the retrieval behavior, the list-all option, the use case, the scoping note, and the pointers to related tools. 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?

Given the tool's simplicity (one optional parameter, no output schema) and rich annotations, the description covers all essential aspects: what the tool does, when to use it, how it behaves (listing vs. retrieval), scoping, and relationship to remember/forget. It is complete enough for an agent to select and invoke the tool correctly without ambiguity.

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 input schema has 100% coverage with a clear description for the single 'key' parameter, so the baseline is 3. The description adds meaningful context beyond the schema by explaining that keys are 'previously saved via remember' and providing examples of key values (target ticker, address, notes), plus clarifying that omitting the key lists all saved keys. This enriches the parameter semantics beyond a bare schema definition.

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 a specific verb and resource: 'Retrieve a value previously saved via remember, or list all saved keys'. It clearly distinguishes from siblings by mentioning 'remember' and 'forget' and provides concrete examples like the user's target ticker or prior research notes, making the tool's purpose unmistakable.

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 says to use this tool 'to look up context the agent stored earlier' and contrasts it with alternatives: 'Pair with remember to save, forget to delete.' This gives the agent a clear decision rule for when to invoke this tool versus related ones, and it even notes the optional key argument for listing all keys.

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