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

The description discloses key behavioral traits beyond the annotations: memory is scoped by identifier, persistence differs for authenticated (persistent) vs anonymous (24 hours) users, and it stores key-value pairs. This adds useful context that the annotations (readOnlyHint, idempotentHint, destructiveHint) do not cover, without contradicting them.

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, front-loaded with the core purpose, then usage context, then storage details. Every sentence contributes meaning, with no redundancy or fluff.

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 tool with no output schema, the description covers all essential aspects: purpose, when to use, persistence behavior, and relationship to sibling tools. The lack of return value details is acceptable given the tool's simplicity.

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 schema description coverage is 100%, with both key and value parameters clearly described and example values provided in the schema. The description adds no additional parameter semantics beyond what the schema already offers, so the baseline score of 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: to save data the agent will need later. It uses specific verbs ('Save data') and provides concrete examples of what to store (ticker, address, preference, research subject). It also distinguishes itself from sibling tools by explicitly referencing recall and forget as complementary operations.

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 gives explicit guidance on when to use the tool: 'Use when you discover something worth carrying forward' and provides examples. It also names the alternatives for retrieval (recall) and deletion (forget), making the decision boundary clear.

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