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

Annotations already indicate idempotentHint=true and destructiveHint=false, so the description adds value by disclosing scoping ('scoped by your identifier') and persistence nuances ('Authenticated users get persistent memory; anonymous sessions retain memory for 24 hours'). It does not contradict annotations, though it could have explicitly mentioned overwrite behavior, but the idempotency hint partially covers that.

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 three sentences long, front-loaded with the primary purpose. Every sentence earns its place: purpose, usage examples, and persistence details. No filler or 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?

For a tool with only two parameters and no output schema, the description covers usage context, persistence, scoping, and sibling relationships. It is missing potential details like error handling or overwrite semantics, but those are not critical given the tool's simplicity and the presence of annotations. Overall, it is sufficiently complete for an agent to use it correctly.

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% (both key and value have descriptions with examples). The description itself mentions 'key-value pair' and gives examples of values, but does not add new parameter-level detail beyond what the schema already provides. Thus, 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 'Save data the agent will need to reuse later' with a specific verb and resource. It distinguishes itself from siblings like 'recall' and 'forget' by explicitly mentioning pairing. The examples of what to save (ticker, address, preference) make the purpose very concrete.

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 explicitly says 'Use when you discover something worth carrying forward' and provides specific scenarios. It also names alternatives: 'Pair with recall to retrieve later, forget to delete.' This gives clear when-to-use and when-not-to-use guidance relative to sibling tools.

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