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

Goes beyond annotations by disclosing scoping ('scoped by your identifier') and retention differences (authenticated users persistent, anonymous sessions 24 hours). Annotations only indicate idempotent and non-destructive write; the description adds meaningful behavioral context 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?

Four sentences, all information-dense and front-loaded with the core action. Every sentence adds value: purpose, usage trigger, storage format, retention policy, and companion tools. No fluff 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 simple key-value store, the description covers purpose, usage, retention, and lifecycle (recall/forget). A minor gap is the lack of explicit mention of overwrite behavior for existing keys, but idempotent annotation implies it. Overall complete for the tool's complexity.

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% with clear descriptions for both 'key' and 'value'. The description reinforces the key-value pair concept but does not add new parameter semantics beyond what the schema already provides. Baseline of 3 applies.

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 memory data), and distinguishes itself from sibling tools by explicitly pairing with 'recall' (retrieve) and 'forget' (delete).

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?

Provides explicit when-to-use guidance: 'Use when you discover something worth carrying forward... so you don't have to look it up again.' It also mentions companion tools for retrieval and deletion, implicitly indicating when not to use this tool (i.e., not for retrieving or deleting).

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