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

Annotations already indicate non-read-only, idempotent, non-destructive behavior. The description adds valuable context not in annotations: key-value scoping, persistence differences between authenticated and anonymous sessions (24 hours), and cross-session reuse. This goes beyond what annotations alone convey.

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 compact and front-loaded with the primary action, followed by contextual use cases and pairing instructions. Every sentence earns its place without redundancy or fluff.

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?

Given the simple 2-parameter schema, strong annotations, and absence of an output schema, the description fully covers the necessary context: what is stored, why, persistence rules, and how it fits with sibling tools. No significant gaps remain.

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% with clear descriptions for 'key' and 'value'. The description adds conceptual meaning by explaining the key-value pair is 'scoped by your identifier' and that the value can be any text. This enriches understanding beyond the schema's basic examples.

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 and resource: 'Save data the agent will need to reuse later' across conversations/sessions. It clearly distinguishes itself from sibling tools 'recall' and 'forget' by defining its role as the storage operation.

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 explicit when-to-use guidance with concrete examples ('a resolved ticker, a target address, a user preference, a research subject') and notes when not to use it by pairing with recall and forget. This is exemplary usage guidance.

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