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

The description adds valuable behavioral context beyond the annotations: it explains the key-value storage model, scoping by user identifier, and the persistence difference between authenticated users (permanent) and anonymous sessions (24 hours). It also mentions the pairing with recall/forget, which clarifies the full lifecycle. 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?

The description is four sentences long, front-loads the core purpose, and then layers usage examples, storage details, and sibling references. Every sentence provides distinct information with no redundancy or filler.

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 write tool with no output schema, the description covers everything needed: purpose, when to use, storage semantics, persistence behavior, and relationships with recall/forget. The tool's complexity is low, and the description is fully sufficient for an agent to invoke 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?

The schema already covers both parameters with detailed descriptions (100% coverage), so the baseline is 3. The description adds extra value with a concrete example for the key format and clarifies that value accepts 'any text,' which helps agents formulate correct inputs. This goes slightly beyond the schema without over-explaining.

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 uses the specific verb 'save' with a clear resource ('data the agent will need to reuse later') and explicitly contrasts with sibling tools by naming 'recall' and 'forget'. This makes the tool's purpose unmistakable and differentiates it from other memory operations.

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 provides explicit 'when to use' guidance with concrete examples (resolved ticker, target address, user preference, research subject). It also names the companion tools (recall, forget) as alternatives, though it does not explicitly state when *not* to use it. The context is strong enough to guide agent selection.

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