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

Disclosures include scoping by identifier, persistence for authenticated users, and 24-hour retention for anonymous sessions—adding value beyond annotations. However, it does not mention whether writing a duplicate key overwrites the value, nor any capacity limits. Minor gap for a storage tool.

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?

Four sentences, front-loaded with purpose. Each sentence adds value: purpose, usage guidance, technical detail, and pairing with related tools. No wasted 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?

Covers purpose, usage, persistence, and pairing. For a simple key-value store with fully described parameters and annotations, this is fairly complete. Missing overwrite behavior and error handling, but likely acceptable given tool simplicity.

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 examples for key and value. The description adds context: stored as a key-value pair scoped by identifier, and purpose ('reuse later'). This provides meaning beyond the schema, justifying a score above the baseline of 3.

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's purpose: 'Save data the agent will need to reuse later.' It specifies the verb 'save' and the resource 'data as key-value pair', and distinguishes itself from siblings like 'recall' and 'forget'. Examples of usage (ticker, address, preference) reinforce the purpose.

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?

Explicitly states when to use: 'Use when you discover something worth carrying forward... so you don't have to look it up again.' It pairs with 'recall' and 'forget' for retrieval and deletion, providing clear guidance on alternatives. Also differentiates 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.