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

Annotations declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: it is scoped to the caller's identifier (anonymous IP, BYO key hash, or account ID), and omitting the key argument lists all saved keys. No contradiction with annotations exists.

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 concise sentences, each earning its place: the first states the core action, the second gives concrete use cases, and the third explains scoping and companion tools. There is no redundant wording or filler.

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 one optional parameter and no output schema, the description is complete. It clarifies what is returned (a value or list of keys), when to use it, and how it relates to remember/forget. The annotations handle safety, and the schema handles parameter structure, leaving no critical gaps.

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 fully documents the optional key parameter, including the 'omit to list all keys' behavior. The description adds the insight that keys are 'previously saved via remember,' which clarifies the provenance of valid keys and reinforces the parameter's semantics beyond the schema text.

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 uses a specific verb-resource pairing: 'Retrieve a value previously saved via remember, or list all saved keys.' It clearly distinguishes the tool from siblings by naming remember and forget as companion operations, and the resource is unambiguous (a saved memory key).

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 explicit use context: 'Use to look up context the agent stored earlier — the user's target ticker, an address, prior research notes — without re-deriving it from scratch.' It also references companions (remember to save, forget to delete), but it does not explicitly state when not to use this tool or list alternative tools for similar purposes.

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