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

Adds important behavioral details beyond annotations: stored as a key-value pair scoped by agent identifier, persistent for authenticated users, 24-hour retention for anonymous sessions. These details are not in the annotations and enhance the agent's understanding of the tool's behavior. No contradiction with 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?

Four sentences, front-loaded with the primary action. Each sentence contributes meaningful information (what, when, persistence, pairing with recalls/forget). No filler or redundancy.

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 memory tool with no output schema, the description covers all essential aspects: purpose, usage triggers, persistence semantics, and relationship to recall/forget. Nothing critical is missing.

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 covers 100% of parameters with descriptions. The tool description repeats the key-value concept but adds no significant new parameter semantics beyond the schema, so 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?

Description opens with 'Save data the agent will need to reuse later', clearly stating the action and resource. It distinguishes from siblings by explicitly pairing with recall and forget, and provides concrete examples of what to store (ticker, address, preference).

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 instructs 'Use when you discover something worth carrying forward' with examples. It also clarifies the relationship to sibling tools 'recall' and 'forget', giving clear context for when to use this tool versus alternatives.

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