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

Beyond the annotations (which indicate a non-read-only, idempotent, non-destructive write), the description adds valuable behavioral context: memory is scoped by identifier, authenticated users get persistent storage, and anonymous sessions retain data for only 24 hours. It also explains the lifetime of the stored data and the relationship to recall/forget, all of which are not present in the annotations.

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 tightly written in three sentences, each earning its place: the core purpose, when to use it with indicative examples, and storage/retention details. It's concise, well-front-loaded, and contains no filler or 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 with no output schema, the description fully captures the necessary context: purpose, use cases, storage scoping, retention period, and companion tools. It provides a complete mental model for how and when to invoke the tool, and the schema covers all parameters. No significant gaps remain.

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 provides full descriptions for both 'key' and 'value' with examples, giving 100% schema coverage. The description mentions 'key-value pair' but adds no extra detail about parameter formats, constraints, or usage semantics beyond what the schema documents. Since the schema carries the load, this is a baseline score.

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 purpose with a specific verb and resource: 'Save data the agent will need to reuse later.' It distinguishes itself from sibling tools by naming pairing with 'recall' and 'forget' and specifies the storage model (key-value pair, scoped by identifier). This makes the tool's role 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?

The description gives explicit when-to-use guidance with concrete examples ('discover something worth carrying forward... a resolved ticker, a target address'). It also mentions pairing with recall and forget, which clarifies the workflow. However, it does not explicitly state when not to use the tool or contrast with alternatives beyond those two complements, so it stops short of full guidance.

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