Echo Write

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered. The description adds genuinely new behavior: idempotency via idempotency_key, content-hash idempotency for overwrite, and the absence of any delete path, clarifying what the destructive hint does and does not mean.

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 short sentences with zero filler; the core action is front-loaded and the idempotency/scope caveats follow. Every clause carries information.

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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile. The description rounds this out with idempotency and delete-scope notes, though it could say more about whether overwrite destroys prior content or what permissions are required.

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 description coverage is only 20% (only idempotency_key is documented), so the description must compensate. It does add real meaning for mode (overwrite vs append) and idempotency_key, but leaves path, content, and create_dirs to be inferred from their names alone.

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 pair ("Write or append UTF-8 text to a local file path") with scope qualifiers (UTF-8, local path). The mutating verb inherently separates it from the `read` sibling, and the append/overwrite modes are named.

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?

Provides one useful boundary ("No delete operation is exposed") and hints at retry semantics, but never says when to choose append vs overwrite or when to prefer this over the `read`/`search` siblings. 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.