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

The description discloses authentication-dependent persistence (authenticated users get persistent memory, anonymous sessions retain memory for 24 hours) and scoping by identifier, which goes beyond the annotations' idempotency hint. No contradiction with annotations exists.

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 with no fluff, front-loading the core action first and quickly moving to usage and persistence details. Every sentence provides new information about purpose, when to use, or behavior.

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?

As a simple key-value store tool with no output schema, the description covers purpose, usage scenarios, persistence behavior, and related tools, which is complete for its complexity. The annotations provide idempotency, so the lack of detail on overwrite behavior is acceptable.

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 already fully documents both parameters with 100% coverage, so the baseline is 3. The description adds the key-value pair concept and scoping by identifier, but this is more about storage behavior than parameter-specific semantics. The schema's examples already cover key and value expectations.

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 with 'Save data the agent will need to reuse later,' specifying both the verb (save) and the resource (data for later reuse). It distinguishes itself from siblings by explicitly mentioning recall and forget as paired tools for retrieval and deletion.

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?

It gives explicit context for when to use it: 'Use when you discover something worth carrying forward...' with concrete examples. It also provides guidance on complementary tools by saying 'Pair with recall to retrieve later, forget to delete,' making the decision framework clear.

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