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

The description adds valuable behavioral context beyond annotations: memory is stored as key-value pairs scoped by identifier, authenticated users get persistent memory, and anonymous sessions retain memory for 24 hours. This goes well beyond what readOnlyHint/idempotentHint provide and does not contradict any annotation.

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 that are front-loaded with purpose, then usage scenarios, then persistence details. No redundant words or fluff; every sentence earns its place.

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, the description is complete: it covers what to store, when to use it, storage scoping, persistence behavior, and companion tools. No important operational detail is missing.

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?

The schema already documents both parameters with examples and descriptions at 100% coverage. The description's examples (resolved ticker, target address) align with schema examples but add no new syntax or format details, so the baseline score of 3 is appropriate.

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 opens with 'Save data the agent will need to reuse later', which clearly states the action (save) and resource (data to reuse). It distinguishes the tool from siblings like recall and forget by specifying cross-conversation/session persistence and providing concrete examples (ticker, address, preference).

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?

It explicitly says 'Use when you discover something worth carrying forward' and lists example scenarios. The final sentence names complementary tools ('Pair with recall to retrieve later, forget to delete'), giving clear guidance on when to use this tool versus alternatives.

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