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

The description adds meaningful behavioral context not in annotations: scoping by identifier, persistent memory for authenticated users, and 24-hour retention for anonymous sessions. It does not explicitly describe overwrite semantics for existing keys, but the idempotentHint annotation already covers idempotency, so this gap is minor.

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 and front-loaded with the core action, then offers practical use cases and lifecycle notes. Every sentence contributes value: purpose, when to use, storage semantics, persistence, and related tools. No wasted words.

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 covers all necessary context: purpose, usage, scoping, persistence, and integration with recall/forget. The agent has enough information to decide when and how to invoke the tool correctly, including authentication implications.

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 coverage is 100% with descriptive examples for both key and value parameters. The description adds little beyond the schema, only reinforcing the key-value concept and providing usage examples in the 'Use when' clause. Since the schema already defines parameter semantics, a baseline score 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 action ('Save data'), the resource (key-value pairs), and the context (across conversations or sessions). It distinguishes from sibling tools by mentioning recall and forget as counterparts, making 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?

Explicitly provides when-to-use guidance with concrete examples ('a resolved ticker, a target address, a user preference, a research subject') and explains the benefit (avoid looking it up again). It also names the complementary tools (recall, forget) and notes the persistence difference for authenticated vs anonymous sessions, shaping when this tool is appropriate.

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