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

Annotations already include destructiveHint=true and idempotentHint=true, so the description doesn't need to restate those. It adds value by specifying what is destroyed (a memory by key) and the typical use cases for deletion. However, it doesn't mention irreversibility or edge cases like missing keys, but that's partially covered by 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 with no wasted words. The first sentence states the core action; the second gives usage triggers. 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 one-parameter delete tool with good annotations, the description provides complete context: what it does, when to use it, and how it relates to sibling tools. No output schema is needed, and idempotency/destructiveness are covered by annotations.

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 description coverage is 100%—the single parameter 'key' is described as 'Memory key to delete.' The description's phrase 'by key' adds no extra meaning beyond the schema, so the baseline 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 a clear verb and resource: 'Delete a previously stored memory by key.' It explicitly distinguishes the tool from siblings by framing it as the counterpart to remember and recall, which are listed in the sibling tools.

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 usage criteria: 'Use when context is stale, the task is done, or you want to clear sensitive data the agent saved earlier.' It also references complementary tools (remember and recall), giving clear context on when this tool is appropriate versus alternatives.

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