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

Annotations already indicate write, idempotent, not destructive. The description adds valuable context: key-value storage, scoping by identifier, persistence differences between authenticated and anonymous sessions (24 hours vs persistent). This goes beyond annotations without contradiction.

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 efficiently structured: purpose first, then usage, then behavioral detail, then pairing. Every sentence adds value; no fluff. Could be slightly more concise, but overall well-organized.

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 tool with no output schema, the description does not explain what the agent can expect as a result (e.g., confirmation, error messages). Overwriting behavior is implied by idempotentHint but not explicit. Missing these details reduces completeness.

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%, so baseline is 3. The description gives examples for key/value but does not add new semantic meaning beyond what the schema's descriptions already provide.

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 uses a specific verb ('Save') and resource ('data... key-value pair') and clearly distinguishes from siblings by mentioning recall and forget. It explicitly states the tool's role in the memory system.

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 context for when to use the tool ('when you discover something worth carrying forward') and gives concrete examples. It also pairs with recall and forget, but does not explicitly state when not to use it.

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