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

With annotations already indicating read-only, idempotent, and non-destructive behavior, the description adds valuable context that data is 'scoped to your identifier (anonymous IP, BYO key hash, or account ID).' It also explains the behavior of omitting the key to list all saved keys and the relationship to remember/forget. This goes beyond the annotations without any contradiction.

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 three sentences, front-loaded with the core action, followed by usage context and scoping details. Every sentence adds distinct value: the first states what the tool does, the second explains when to use it, and the third provides scoping and sibling relationships. There is no redundancy or fluff.

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 tool with one optional parameter, the description covers all essential aspects: action, argument behavior, use cases, scoping, and related tools. It includes security/privacy context via identifier scoping, and the lack of an output schema is acceptable given the straightforward nature of 'retrieve value' or 'list keys.' The description is complete for the tool's complexity.

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 already covers the single parameter with 100% coverage ('Memory key to retrieve (omit to list all keys)'), so the baseline is 3. The description echoes the omit behavior and gives examples of saved values, but these are contextual illustrations rather than new parameter semantics. The parameter is simple and fully documented, so no additional explanation is 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 clearly states the tool's action ('Retrieve a value previously saved via remember, or list all saved keys') and specifies the resource (saved memory values). It distinguishes itself from sibling tools by naming remember and forget as the counterpart actions, and provides concrete examples of use cases (user's target ticker, address, research notes). This is a specific verb+resource+scope formulation.

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 'Use to look up context the agent stored earlier... without re-deriving it from scratch,' which gives clear when-to-use guidance. It also instructs on the argument behavior ('omit the key argument' to list all keys) and points to alternatives via 'Pair with remember to save, forget to delete,' establishing a clear workflow and contrasting with sibling tools.

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