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

Annotations cover idempotency and non-destructiveness, but the description adds crucial context about scope (by identifier), persistence differences (authenticated vs. anonymous 24-hour retention), and the key-value storage format. This goes beyond the annotations, though it stops short of specifying overwrite semantics or error handling.

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?

Three sentences, front-loaded with the main purpose, and each sentence adds distinct value: what it does, when to use it, and how it stores data. No filler or redundancy.

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 two-parameter tool with no output schema and helpful annotations, the description covers all essential aspects: functionality, usage triggers, persistence behavior, and tool relationships. It is complete and self-sufficient for an agent to select and use it correctly.

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 already provides 100% parameter coverage with descriptions, so baseline is 3. However, the tool description adds meaning by explaining the key-value pairing and 'scoped by your identifier', which helps the agent understand how parameters interact and why uniqueness matters. The example keys ('subject_property', 'target_ticker') further clarify expected values.

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 'Save data the agent will need to reuse later', with a specific verb and resource (memory). It distinguishes itself from siblings by explicitly mentioning pairing with 'recall' and 'forget', making its role in the persistent-memory lifecycle unambiguous.

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?

Provides explicit when-to-use guidance ('Use when you discover something worth carrying forward') and names complementary tools ('Pair with recall to retrieve later, forget to delete'), which frames the correct context for usage versus alternatives.

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