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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds scoping details (anonymous IP, BYO key hash, account ID) and the behavior of omitting the key to list all keys—context beyond what annotations provide. It is not overly rich but adds meaningful value.

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 primary action. Each sentence earns its place: the first states what it does, the second explains when to use it, and the third adds scoping and pairing context. No wasted words 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?

For a simple tool with one optional parameter and no output schema, the description is complete enough. It explains the core retrieval and listing behavior, scoping, and relationship to siblings. It does not specify return format, but the behavior—retrieving a value or listing keys—is unambiguous. Given the lack of an output schema, a brief note on return type would be slightly beneficial but is not necessary for correctness.

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?

Schema coverage is 100% and the schema description already explains the key parameter and the omit-to-list behavior. The description provides examples of keys ('user's target ticker, an address, prior research notes') but adds no additional parameter syntax or format details, so it does not exceed the baseline of 3.

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 function: 'Retrieve a value previously saved via remember, or list all saved keys (omit the key argument).' It uses a specific verb and resource, and distinguishes itself from sibling tools 'remember' and 'forget' by describing its complementary role.

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?

Explicitly says 'Use to look up context the agent stored earlier' and provides concrete examples of what to store (target ticker, address, research notes). It also names alternatives and complements: 'Pair with remember to save, forget to delete.' This gives clear when-to-use guidance and differentiates from siblings.

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