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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the baseline for extra value is lower. The description adds meaningful behavioral context beyond annotations: the tool is scoped to the caller's identifier (anonymous IP, BYO key hash, or account ID), and omitting the key lists all saved values. This clarifies data isolation and dual-mode behavior, though it does not cover return formats or error handling.

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 main action and behavior. The second sentence illustrates use cases, and the third covers scoping and related tools. Every sentence contributes value with no redundancy or fluff, achieving excellent brevity for the information conveyed.

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?

With one optional parameter, no output schema, and annotations covering safety, the description is fully adequate. It explains the dual behavior (retrieve vs. list), scoping, and integration with remember/forget. Nothing critical is missing for an agent to select and invoke this tool correctly.

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 provides 100% coverage for the single parameter, describing the key as 'Memory key to retrieve (omit to list all keys).' The description reiterates the same semantic in prose without adding new parameter-level details. With full schema coverage, the baseline of 3 applies; the description adds no additional parameter semantics.

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.' This clearly distinguishes the tool from its siblings (remember, forget) by describing both retrieval modes. The added examples of stored context (ticker, address, research notes) reinforce the purpose without ambiguity.

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 states when to use the tool: 'Use to look up context the agent stored earlier... without re-deriving it from scratch.' It also identifies related tools for alternative operations: 'Pair with remember to save, forget to delete.' This provides clear contextual guidance and excludes the need for re-derivation, making usage intent unambiguous.

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