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

Annotations already declare idempotentHint=true and destructiveHint=false, and the description adds meaningful context: key-value storage scoped by identifier, persistent memory for authenticated users, and 24-hour retention for anonymous sessions. This goes beyond the annotations by explaining the actual storage semantics and lifetime.

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, each earning its place: what it does, when to use it, storage semantics, and sibling routing. The most important information is front-loaded, and there is zero filler.

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?

Complete for a simple two-parameter key-value store. The description covers purpose, usage, storage behavior, and related tools. No output schema exists, but the operation is simple enough that return value details are not critical for correct invocation.

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 description coverage is 100%, so the schema already documents both parameters. The description adds the key-value pair framing and examples of keys, but doesn't add substantial meaning beyond what the schema provides. 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 states a specific verb ('Save') and resource ('data the agent will need to reuse later'), and clearly distinguishes it from siblings by naming recall and forget as complementary operations. It also gives concrete examples of what to store, making the tool's purpose immediately actionable.

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 when to use it ('when you discover something worth carrying forward') and provides examples of the kinds of information to save. It also names the sibling tools for related operations ('Pair with recall to retrieve later, forget to delete'), giving clear routing guidance.

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