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

Annotations already indicate the operation is non-read-only, idempotent, and non-destructive. The description adds significant context beyond these flags: key-value storage scoped by identifier, and persistence differences between authenticated (persistent) and anonymous (24-hour) sessions. This helps set expectations about data retention and scope 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 three sentences, front-loaded with purpose, followed by usage and storage details. Every sentence adds value, and there is no redundancy or filler. It is concise while covering the essential aspects.

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 save operation, the description covers purpose, when to use, storage behavior, persistence, and companion tools. The input schema fully documents parameters, and annotations cover safety traits, so nothing essential is missing. The absence of an output schema is acceptable since the tool likely returns minimal acknowledgment.

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 coverage is 100%, so the parameters are already well-documented. The description mentions the key-value pair concept and scoping by identifier, which reinforces the relationship between parameters, but it does not add new parameter-level semantics beyond the schema's examples. 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 explicitly states the tool saves data for later reuse, with a specific verb 'Save' and resource 'data... to reuse later'. It clearly distinguishes itself from siblings by referencing recall and forget, which are complementary rather than alternative purposes.

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 clear when-to-use guidance: 'Use when you discover something worth carrying forward' with concrete examples. It also explicitly names alternatives: 'Pair with recall to retrieve later, forget to delete.' This gives the agent decision rules for choosing this tool over siblings.

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