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

Annotations already declare idempotency and non-destructiveness. The description adds valuable context beyond annotations: memory scoping by identifier, persistence differences for authenticated vs. anonymous sessions (24-hour retention), and the key-value storage model. This enriches the agent's understanding of side effects and lifespan.

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 compact yet information-dense. It front-loads the primary purpose, then provides usage context, persistence details, and sibling tool relationships in a logical flow. Every sentence contributes new information, with no redundancy or fluff.

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 the tool's simplicity (2 parameters, no output schema), the description covers all essential aspects: what it does, when to use it, how data is scoped and retained, and how it integrates with related tools. It leaves no significant contextual gaps for an agent to operate correctly.

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 already covers both parameters with detailed descriptions and examples (100% coverage). The description's mention of 'key-value pair' adds no new semantic detail beyond what the schema provides, so it meets the baseline for high schema coverage.

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 opens with a specific verb and resource: 'Save data the agent will need to reuse later.' It clearly distinguishes itself from siblings by naming paired tools (recall, forget) and explaining the memory use case. The resource (memory) is 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?

Provides explicit when-to-use guidance with concrete examples ('a resolved ticker, a target address, a user preference'). It names alternative tools (recall, forget) but does not explicitly state when NOT to use this tool. The absence of a 'when-not' clause keeps it slightly below a perfect score.

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