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

Annotations already indicate idempotent and non-destructive behavior, but the description adds valuable context: memory is scoped by identifier, authenticated users get persistent memory, and anonymous sessions retain data for 24 hours. This goes beyond the annotations 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 primary purpose, and every sentence adds value: it defines behavior, gives usage examples, and mentions retention and companion tools. 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 simple two-parameter write tool with no output schema, the description covers storage semantics, authentication-based persistence, anonymous retention limits, and companion tools. Overwrite behavior is not mentioned but is non-essential for basic usage, so the description is sufficiently 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 schema provides 100% coverage of the two required parameters, including examples for the key and a description for the value. The description reinforces semantics with use-case examples but does not add new parameter format or syntax details, so the 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 opens with a specific action, 'Save data the agent will need to reuse later,' and clearly identifies the resource as a key-value memory store. It distinguishes itself from siblings by explicitly naming recall and forget as complementary tools, and by emphasizing cross-session persistence.

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 provides explicit usage triggers with examples such as a resolved ticker, target address, or user preference, and directs the agent to pair with recall and forget for retrieval and deletion. However, it does not explicitly state when not to use this tool or contrast it with other storage/retrieval alternatives.

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