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

Beyond the annotations, the description adds key behavioral details: key-value pair scoping by agent identifier, persistent memory for authenticated users, and 24-hour retention for anonymous sessions. It discloses retention and scoping, which are not covered by the annotations, and does not contradict any hints (idempotentHint=true aligns with the nature of saving).

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 four sentences long, front-loaded with the core purpose, and each sentence adds distinct value: definition, usage, storage semantics, and pairing with sibling tools. There is no redundancy or 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?

For a simple two-parameter tool with no output schema, the description covers all essentials: what it does, when to use it, how data is stored, persistence behavior, and related tools. The low complexity means this is fully sufficient for an agent to select and invoke the tool correctly.

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. The description adds semantic context by giving specific examples of what to store (resolved ticker, target address, user preference), which helps the agent choose appropriate keys and values, providing value beyond the schema's field descriptions.

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 saves data for later reuse across conversations or sessions, using the specific verb 'save' with the resource 'data'. It distinguishes itself from sibling tools by explicitly naming recall and forget as counterparts 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 provides concrete when-to-use guidance with examples like 'a resolved ticker, a target address, a user preference' and explains the alternative tools ('Pair with recall to retrieve later, forget to delete'). This makes the usage context unambiguous relative to its siblings.

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