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

The description adds valuable context beyond the annotations: memory is scoped by identifier, authenticated users get persistent memory, and anonymous sessions retain data for 24 hours. It also implies overwriting behavior via idempotentHint. No contradiction with annotations exists, and the added retention details are useful.

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 composed of five concise, purposeful sentences. It front-loads the core purpose, then provides usage scenarios, storage details, retention behavior, and pairing with related tools. No sentences are wasted, and the structure is easy to scan.

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, the description is complete: it covers purpose, when to use, storage scope, retention, and related operations. No output schema is needed, and the description fully compensates for the lack of additional structured context. The behavior is fully specified for an agent.

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 description coverage is 100%, so the baseline is 3. The description adds examples of key names (e.g., "subject_property", "target_ticker") and says value is "any text," but these largely mirror the schema's parameter descriptions. It does not introduce meaning beyond what the schema already provides, so a 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 tool's function: "Save data the agent will need to reuse later." It uses a specific verb (save) and resource (key-value pair data), and distinguishes it from sibling tools by naming recall and forget for retrieval and deletion. Examples like "resolved ticker" and "user preference" further clarify the intended use.

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?

Explicit usage guidance is provided: "Use when you discover something worth carrying forward." The description also explains when to use alternatives (recall to retrieve, forget to delete) and clarifies persistence differences between authenticated and anonymous sessions. This fully addresses when and how to use the tool versus its siblings.

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