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

Annotations provide idempotentHint=true and destructiveHint=false, but the description adds essential context: scoped by identifier, persistence differences between authenticated (permanent) and anonymous (24 hours). No contradiction with 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?

Four succinct sentences, each contributing value: core purpose, usage context, storage details, and companion tools. No fluff; front-loaded with the main action.

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 memory tool with two parameters and no output schema, the description covers purpose, when to use, storage behavior, scoping, and persistence. Referencing recall and forget completes the mental model.

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 descriptions already cover both key and value. The description adds value by giving examples of key patterns (e.g., 'subject_property', 'target_ticker') and clarifies that value can be any text, augmenting 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 clearly states the verb (Save) and resource (data to reuse later), and distinguishes from siblings by mentioning paired tools recall and forget. Examples of what to store (ticker, address, preference) make it highly specific.

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 (discover something worth carrying forward) and provides concrete scenarios. It also mentions companion tools for retrieval and deletion, guiding the agent on workflow.

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