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

Adds important behavioral details beyond annotations: scoping by identifier, persistence duration (permanent for authenticated, 24h for anonymous), and non-destructive nature (overwriting key-value pairs). No contradictions with idempotentHint=true.

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 with front-loaded purpose, then usage, behavior, and tool pairing. No redundant phrases, every sentence adds value.

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?

Complete for a simple key-value store: explains when to use, what it does, behavioral nuances, pairing with siblings, and parameter usage. No output schema needed for such a tool; description covers return expectations implicitly.

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 baseline is 3. Description adds concrete examples for keys (e.g., 'subject_property', 'target_ticker') and clarifies value accepts any text, which helps agents format inputs correctly.

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?

Clear verb 'save data' and specific resource 'key-value pair' with explicit use cases (resolved ticker, target address, user preference). Distinguishes from sibling tools recall and forget directly.

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: 'when you discover something worth carrying forward... so you don't have to look it up again.' Also mentions pairing with recall and forget, and provides persistence context for authenticated vs anonymous users.

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