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

Annotations already clearly indicate destructiveHint=true and readOnlyHint=false, so the agent knows this is a mutation. The description adds that it clears "previously stored memory" and can be used for sensitive data, but doesn't add further behavioral details like whether deletion is permanent or if there are any side effects. It doesn't contradict 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 two sentences, well-structured, and front-loaded with the core action. Every word earns its place, 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?

The tool is simple (one parameter, no output schema) and annotations provide the safety profile. The description covers the purpose and usage context. It doesn't explain return values, but that's unnecessary given the absence of an output schema. Sibling tools like remember and recall provide the surrounding context.

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%, as the only parameter 'key' is described as 'Memory key to delete'. The description adds the phrase 'by key' but doesn't go beyond the schema. The schema already does the heavy lifting, so a baseline 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 states exactly what the tool does: "Delete a previously stored memory by key." This clearly defines the action (delete), resource (memory), and scope (by key). It also distinguishes from sibling tools remember and recall by indicating the opposite operation.

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?

The description gives explicit usage conditions: "Use when context is stale, the task is done, or you want to clear sensitive data the agent saved earlier." It also mentions pairing with remember and recall, implying these are complementary tools. However, it doesn't explicitly say when not to use it or provide direct alternatives, so it falls just short of a 5.

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