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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the destructive nature is known. The description adds 'previously stored' and 'saved earlier' context but does not disclose additional behavioral traits beyond annotations (e.g., what happens if the key doesn't exist). No contradiction found.

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?

Two sentences, no filler. The first sentence front-loads the action and object; the second provides usage context and sibling references. Every word 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?

The tool is simple (1 required parameter, no output schema). The description explains what it does, when to use it, and how it relates to sibling tools. It does not describe return values or error behavior, but that is not expected given the lack of output schema and the annotations covering safety.

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 has 100% coverage for the single parameter 'key' with description 'Memory key to delete'. The description adds no extra meaning beyond the schema; it only repeats 'by key'. The schema already does the heavy lifting.

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 action ('Delete a previously stored memory by key') and the resource ('memory'). It distinguishes the tool from siblings like 'remember' (store) and 'recall' (retrieve) by explicitly naming them in the usage guidance.

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 when-to-use scenarios: 'context is stale, the task is done, or you want to clear sensitive data.' It also names complementary tools ('Pair with remember and recall'), giving clear situational guidance.

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