Write (replace) Markdown section

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

With no annotations, the description carries the full behavioral burden, and it uses the opportunity well: it discloses that this is a destructive replacement, precisely what gets destroyed (body content only), and what is preserved (heading, all other sections). This directly answers the main risk question for a mutation tool — 'what will I lose?' The only gap is failure behavior when the selector matches no section or the file doesn't exist.

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 sentences, each earning its place: core action, key nuance (heading preserved), and scope guarantee (other sections untouched). Every word is load-bearing, and the critical safety detail is front-loaded in the second sentence. There is no filler or repetition of schema content.

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 mutation tool with no annotations and no output schema, the description covers the change semantics well but stays silent on outcomes and failure modes — whether the file must exist, whether a non-matching selector is an error or a no-op, and what the tool returns on success. These are the remaining gaps an agent needs to call it safely.

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 the baseline is 3, but the description adds meaning the schema lacks: it connects 'selector' to 'structural location,' clarifies that 'content' is body-only, and explains the heading/body relationship that the individual parameter descriptions don't state. It doesn't describe the selector syntax (already covered by the schema example), so it stops short of 5.

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 specific verb and resource — 'Replaces the content at a structural location' — and immediately adds the two distinguishing nuances: the heading survives and the rest of the document is untouched. Combined with the title 'Write (replace) Markdown section,' an agent can easily separate this from the read, append, delete, query, and tree siblings without opening their schemas.

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 implies its use case — replacing body content within a section while preserving the heading — but never names a sibling or states when to prefer an alternative like nodiom_append or nodiom_delete. An agent must infer the boundary between replace, append, and delete purely from the sibling names. The scoping sentence ('All other sections in the document are untouched') provides context but no explicit routing.

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