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

Description adds scoping and pairing context beyond annotations. Annotations already indicate readOnlyHint, idempotentHint, destructiveHint; description reinforces the safe, read-only nature and explains the coupling with remember/forget.

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?

Two sentences, front-loaded with action and dual purpose. No wasted words; every sentence adds essential information.

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?

Given one optional parameter, full schema coverage, clear annotations, and no output schema, the description is complete. It covers both retrieval and listing, and pairs with sibling tools.

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% with a brief description. Tool description enhances by explaining the effect of omitting the key (list all keys) and adding scoping context, going beyond the schema's minimal info.

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 dual functionality: retrieving a specific saved value or listing all keys. It provides concrete use-case examples (ticker, address, notes) and distinguishes from sibling tools remember and forget.

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 describes when to use (look up previously stored context) and implies when to list keys (omit argument). Mentions scoping to an identifier. Lacks explicit 'when not to use' but provides sufficient guidance.

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