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

Given annotations declare idempotentHint=true and no destructiveHint, the description adds valuable context: key-value scoping by identifier, persistence for authenticated users, 24-hour retention for anonymous sessions. No contradictions.

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, zero wasted words. The description is front-loaded with the core purpose, followed by usage context and behavioral details. Perfectly structured for AI consumption.

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?

Despite lacking an output schema, the description covers what the tool does, its scope, persistence behavior, and relationship to siblings. No gaps remain for the agent to infer incorrectly.

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 clear parameter descriptions. The description adds value by providing example keys and clarifying that the value is free-text, but the schema already captures the essential meaning.

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 clear verb ('Save data') and resource ('the agent will need to reuse later'), and explicitly separates from sibling tools 'recall' and 'forget', making the tool's purpose unmistakable.

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 states exactly when to use this tool ('when you discover something worth carrying forward'), provides concrete examples, and contrasts with 'recall' and 'forget' for retrieval and deletion.

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