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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely useful context beyond that: the replacement overwrites the entire body including frontmatter, which warns the agent that hand-edits and metadata will be lost. It stops short of describing error behavior or what the call returns.

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 front-loaded sentences that establish purpose before the clarifying detail; no wasted prose. The docs link is mildly extraneous but plausibly useful for deeper semantics.

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, no-output-schema write tool, the definition covers the overwrite semantics but leaves open whether the skill must pre-exist, what happens on invalid frontmatter, and how it relates to skill_file_write. Adequate but with clear gaps an agent would hit at invocation time.

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 100%, so baseline is 3, but the description adds a real clarification beyond the schema by specifying that 'body' must include frontmatter, resolving a genuine ambiguity about whether metadata is separate. It adds nothing for 'name' beyond the schema's own example.

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+resource ('Create a skill or replace the body of an existing one') and covers both create and overwrite modes. It doesn't distinguish itself from the adjacent skill_file_write sibling, so an agent must infer the scope difference (whole skill vs single file).

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 'create or replace' framing implies when to reach for this tool, but there is no explicit guidance on when to use skill_file_write instead, nor on prerequisites (must the skill exist first?). Usage is implied rather than stated.

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