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

The description adds meaningful context beyond annotations by disclosing that data is stored as a key-value pair scoped by the agent's identifier, and that persistence varies by auth status (persistent for authenticated users, 24 hours for anonymous). It does not explicitly mention overwrite behavior, but the idempotentHint annotation already signals that repeated saves are safe, so the description adds valuable extra details without contradicting the 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 a compact paragraph with the main purpose front-loaded, followed by concrete examples, storage mechanics, and important caveats. Every sentence earns its place, with 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 two-parameter tool with no output schema, the description covers the full behavioral picture: what it saves, when to use it, how it is scoped, persistence rules, and related tools. This is sufficient for an agent to select and invoke the tool correctly in real scenarios.

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 already fully describes both parameters (key and value) with examples, achieving 100% coverage. The description contributes illustrative use cases but no additional syntax or constraints beyond what the schema provides, so it meets the baseline but does not elevate it.

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 action ('Save data') with a clear resource (data the agent will need to reuse later), and provides concrete examples ('resolved ticker', 'target address', 'user preference', 'research subject'). It distinguishes the tool from siblings by explicitly naming recall and forget as companions for retrieval and deletion, making the purpose unambiguous.

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 gives 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 states how to complement with other tools ('Pair with recall to retrieve later, forget to delete') and notes persistence differences based on authentication status, which helps the agent choose appropriately.

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