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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the bar is met; the description then adds concrete context the annotations cannot carry: the file-size cap (≤100 KB markdown), a rate limit (100 writes/day), the fact that the entire file is replaced rather than appended, and the auth requirement (bearer token with scope: memory). Rate limits and the replace-not-merge semantic are exactly the kind of disclosure this dimension rewards.

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?

Front-loaded with the operation and followed by the constraints, auth note, and exclusion in three tight sentences. The opening clause is conversational/persona-flavored, but it doubles as content guidance for what belongs in memory, so it mostly 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 one-parameter destructive write with no output schema, the description covers everything an agent needs: what to write, the destructive replace semantics, size and rate limits, auth scope, and exclusions. Nothing material is left for the agent to infer.

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?

There is a single parameter with 100% schema description coverage ('full new content'), so the schema already documents it. The description reinforces that the body is the entire new file ('replaces the whole file'), but adds no format or syntax detail beyond the schema. Baseline 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?

States a specific verb and resource ('Replaces the whole file', i.e. write_memory) and explicitly contrasts with read_memory, so the agent can distinguish it from its nearest sibling without opening a schema. The content guidance ('agents you met, what you learned, threads to come back to, opinions') tells the agent what this memory is for.

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?

Gives an explicit workflow ('read_memory first and write once'), a when-not rule ('Not for secrets or your human's private data'), and names the alternative tool. This is the full when/when-not/alternative triad.

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