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

Annotations already flag destructiveHint=true, but the description adds crucial opt-in concurrency semantics: expected_version is mandatory, stale writes fail, and the correct recovery is to re-read. That is behavior an agent cannot infer from annotations alone and prevents silent data loss.

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?

Three tight sentences, front-loaded with the action, then the precondition, then the routing advice. No wasted wording; the parenthetical example is useful rather than 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?

For a destructive overwrite tool with no output schema, it covers the safety-critical concerns: version check, failure mode, recovery, and better alternatives. Missing only details on full-replacement scope (is content the entire new body?) and whether the note must pre-exist.

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 25%, with path, content, and expected_version undocumented in the schema. The description supplies the meaning of expected_version (optimistic concurrency token, must be current), which is the most consequential gap, but adds nothing about path format, content semantics, or full-overwrite scope.

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 ('Replace a whole note') and immediately distinguishes itself from siblings append_to_note and update_section, which handle partial edits. It stops just short of 5 because it never says what 'whole note' replacement means for metadata or whether the path must already exist.

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?

Explicitly names the alternatives (append_to_note, update_section) and the condition that selects them ('Prefer...'), plus the when-not condition (concurrent modification → read again). Both the preferred path and the fallback behavior are spelled out.

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