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

Discloses key traits beyond annotations: 'Stored as a key-value pair scoped by your identifier', 'Authenticated users get persistent memory; anonymous sessions retain memory for 24 hours.' Adds context on scoping and retention that annotations alone don't provide.

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?

Multiple sentences but tightly written with no waste. Front-loaded with core purpose, followed by usage triggers, then storage details, then pairing instructions. Every sentence earns its place.

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 write-only tool with no output schema and clear annotations, the description provides all necessary context: purpose, when to use, storage behavior, scoping, retention, and sibling relationships. No gaps.

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. Description adds extra meaning: explains that key-value is scoped by identifier, gives example patterns in key description ('subject_property', 'target_ticker'), and defines value as 'any text'. This goes beyond bare schema.

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 'Save data the agent will need to reuse later', specifying the verb 'save' and resource 'data'. It distinguishes from sibling tools 'recall' and 'forget' by naming them for retrieval and deletion.

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 tells when to use: 'when you discover something worth carrying forward'. Provides clear alternatives: 'Pair with recall to retrieve later, forget to delete.' This gives solid guidance on selection among siblings.

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