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

The description adds behavioral context beyond annotations: key-value pair scoped by identifier, persistent memory for authenticated users, 24-hour retention for anonymous sessions, and explicit pairing with recall/forget. The idempotentHint is consistent with overwriting behavior. Minor gap: does not explicitly state that repeated calls with same key overwrite the value.

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 concise: one paragraph with five sentences, each adding value. It front-loads the purpose and follows with usage guidelines, storage details, and pairing with siblings. No unnecessary words.

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?

The description covers all necessary aspects: purpose, usage, storage duration, scoping, and pairing with related tools. Since there is no output schema, the description appropriately focuses on input and behavior. It is fully complete for a simple key-value store tool.

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 both parameters. The description provides additional semantic context with examples (e.g., key naming 'subject_property', value as any text), which helps agents understand parameter conventions beyond the schema.

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 starts with a clear verb and resource: 'Save data the agent will need to reuse later', and provides concrete examples (resolved ticker, target address). It distinguishes this tool from sibling tools 'recall' and 'forget' by explicitly pairing with them.

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 mentions alternatives ('Pair with recall to retrieve later, forget to delete'). It also clarifies scope differences between authenticated and anonymous sessions.

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