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

The description adds behavioral context beyond annotations: it explains that authenticated users get persistent memory while anonymous sessions retain memory for 24 hours. This does not contradict annotations (idempotentHint=true is consistent with key-value storage), and the description clarifies scope and lifetime.

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 concise with 4 sentences, each serving a distinct purpose: stating the main action, providing usage guidance, explaining storage behavior, and mentioning related tools. It is front-loaded with the primary purpose and contains no redundant 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?

For a simple two-parameter tool without an output schema, the description covers all essential aspects: purpose, when to use, parameter roles, behavioral details (persistence), and relationships with sibling tools. It is fully sufficient for an agent to use 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 input schema already covers both parameters with good descriptions (e.g., 'Memory key (e.g., "subject_property")' and 'Value to store (any text)'). The description does not add additional semantic detail beyond schema coverage, so it meets the baseline expectation.

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 starts with a specific verb 'Save data the agent will need to reuse later' and clearly identifies the resource as key-value memory. It distinguishes from sibling tools by explicitly mentioning 'Pair with recall to retrieve later, forget to delete' and contrasting with other tools like 'recall' and 'forget' in the sibling list.

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 clear when-to-use guidance: 'Use when you discover something worth carrying forward' with concrete examples like 'resolved ticker, a target address, a user preference'. It also explains the storage mechanism (key-value pair scoped by identifier) and mentions pairing with recall and forget, offering alternatives.

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