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

The description adds valuable behavioral context beyond the annotations: memory is scoped by the agent's identifier, authenticated users get persistent storage, and anonymous sessions retain memory for 24 hours. It doesn't explicitly mention overwrite behavior for existing keys, but the idempotentHint annotation partially covers this, and the described scoping and retention rules are significant additions.

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 compact sentences, front-loaded with the core action ('Save data...'), followed by usage context and storage details. There is zero redundancy—every sentence adds necessary information, and the structure is logical and easy to scan.

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 2-parameter tool with a 100%-covered schema and informative annotations, the description fully covers the operation, when to use it, storage scope, and retention policy. Since no output schema exists or is needed, the description is sufficiently complete for an agent to invoke the tool 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 covers 100% of the parameters, including types and examples for key and value. The description reinforces the key-value nature ('Stored as a key-value pair') and gives examples of values ('findings, addresses, preferences, notes'), but it doesn't add substantive new syntax or format details beyond the schema. With full schema coverage, the baseline of 3 is appropriate.

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 saves data for later reuse, using the specific verb 'Save' and resource 'data' (memory). It also distinguishes itself from sibling tools by explicitly naming recall (retrieve) and forget (delete), giving concrete examples of what to store.

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: 'Use when you discover something worth carrying forward' and gives examples. It also names alternatives with clear pairings: 'Pair with recall to retrieve later, forget to delete,' effectively telling the agent when not to use this tool.

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