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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral details: the ability to list all keys by omitting the key argument, scoping to an identifier (anonymous IP, BYO key hash, or account ID), and the relationship with remember/forget. This goes beyond minimal annotation-driven expectations, but not to an extremely rich level, so a 4 is appropriate.

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 four sentences, front-loaded with the primary action. Each sentence earns its place: it explains the two modes, gives usage context, mentions scoping, and ties to sibling tools. No redundant or vague phrasing. This is a model of concise, structured documentation.

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 tool with one optional parameter and no output schema, the description is fully complete. It covers the two behaviors (get and list), provides illustrative examples of what to store, notes scoping, and explains when to use the tool relative to its siblings. Nothing essential is missing.

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 covers 100% of parameters with a basic description, giving a baseline of 3. The tool description enriches the 'key' parameter by providing concrete examples of key values (target ticker, address, research notes) and explicitly stating the behavior when omitted (list all keys). This adds meaningful semantic context beyond the schema, so a 4 is warranted.

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'. It specifies the resource (a saved value or list of keys) and distinguishes it from sibling tools remember and forget with 'Pair with remember to save, forget to delete.' This makes the purpose unambiguous.

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 guides when to use the tool: '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 explains the alternative actions (remember to save, forget to delete), providing clear usage context relative to siblings.

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