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

Annotations already declare destructiveHint=true and idempotentHint=true. The description adds that it deletes 'previously stored memory' and mentions clearing 'sensitive data,' which gives some behavioral context. However, most of the destructive behavior is already conveyed by the annotations, and the description does not add details about reversibility or failure outcomes.

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, front-loaded with the core action, and every clause adds value (usage context and related tools). There is no wasted wording.

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 single-parameter delete tool with annotations covering safety, the description is complete enough. It tells what the tool does, when to use it, and how it relates to other memory tools. The lack of output schema is acceptable since the tool is straightforward, though it could mention behavior for missing keys (but idempotentHint already implies safe no-op).

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 input schema fully describes the single parameter 'key' with a clear description. The description repeats 'by key' but adds no extra semantic detail. With 100% schema description coverage, the baseline of 3 applies.

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's function with a specific verb and resource: 'Delete a previously stored memory by key.' This directly distinguishes it from sibling tools like 'remember' and 'recall' by indicating the delete 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 provides explicit use cases: 'Use when context is stale, the task is done, or you want to clear sensitive data.' It also mentions pairing with remember and recall, which gives context on related tools. However, it does not explicitly state when not to use the tool, so it falls 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.