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

Annotations indicate idempotentHint=true and destructiveHint=false, which the description supports by stating 'stored as a key-value pair' and describing persistence (authenticated vs anonymous). It adds behavioral context beyond annotations, such as scoping by identifier and 24-hour retention for anonymous sessions.

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 a single, well-formed paragraph. The first sentence states the core purpose, followed by usage guidance, then details on scoping and persistence. Every sentence contributes meaning with no redundancy.

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?

Given no output schema, the description sufficiently explains the result (data is stored) and provides persistence details. It lacks mention of size limits or error cases, but for a simple memory tool with clear inputs, it is adequately complete.

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?

The input schema has 100% coverage with descriptions for both 'key' and 'value'. The description adds examples (e.g., 'subject_property', 'target_ticker') but does not significantly enhance meaning beyond the schema. Baseline 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 purpose: 'Save data the agent will need to reuse later' using key-value pairs. It distinguishes from siblings by explicitly mentioning 'Pair with recall to retrieve later, forget to delete.' The verb 'save' and resource 'data' are specific.

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 explains when to use: 'when you discover something worth carrying forward... so you don't have to look it up again.' It provides context (scoped by identifier, persistence based on auth) but lacks explicit when-not-to-use or alternative tools beyond recall/forget.

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