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

Annotations provide idempotentHint=true and readOnlyHint=false, but the description adds substantive behavioral context: key-value storage scoping by identifier, persistence differences between authenticated and anonymous users (24-hour retention), and the ability to pair with recall/forget. No contradiction with annotations.

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, each earning its place: purpose, usage triggers, and persistence details. It is front-loaded with the core action and avoids redundancy, making it easy to scan.

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 key-value store with good annotations and no output schema, the description covers all essential aspects: purpose, when to use, persistence, scoping, and how to interact with related tools. Nothing critical is missing.

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 fully documents both parameters. The description adds examples of what to store (resolved ticker, target address, user preference) but these are illustrative, not strictly necessary. Baseline 3 is appropriate as the schema already carries the semantic weight.

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 verb and resource: 'Save data the agent will need to reuse later.' This clearly distinguishes the tool from its sibling tools recall and forget, and the phrase 'across this conversation or across sessions' adds scope.

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 states when to use the tool ('Use when you discover something worth carrying forward') and offers practical examples. It also names complementary tools: 'Pair with recall to retrieve later, forget to delete,' providing clear usage guidance versus alternatives.

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