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

Annotations already indicate read-only, idempotent, and non-destructive behavior. The description adds valuable context beyond annotations: scoping to the agent's identifier (anonymous IP, BYO key hash, or account ID) and the detail that omitting the key lists all saved keys. It does not cover error cases or return value specifics, but the annotation coverage lowers the bar.

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 two sentences with no filler. The primary action and the secondary list mode are front-loaded in the first sentence, followed by use cases and scoping in the second. Every clause earns its place, making it both concise and informative.

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 provides sufficient context: purpose, usage examples, scoping, and relationship to complementary tools. It does not explain return values, but the tool's functionality is straightforward and the description covers the key decision-making needs of an agent.

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% (the 'key' property is described). The description adds meaning by explaining that omitting the key lists all keys, which is critical for using the optional parameter. The examples of potential key values (target ticker, address) help illustrate semantics without being redundant.

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 a specific verb and resource: 'Retrieve a value previously saved via remember, or list all saved keys.' It distinguishes itself from sibling tools by explicitly naming the paired remember and forget tools, making its role in the memory system immediately apparent.

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 provides explicit guidance on when to use the tool: 'Use to look up context the agent stored earlier... without re-deriving it from scratch.' It also explains the alternative by mentioning 'Pair with remember to save, forget to delete,' which sets clear usage boundaries.

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