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

The description goes well beyond the destructiveHint annotation by explaining that 'a version snapshot is saved first, so the change can be undone from letX's history.' It also discloses the replace-vs-create behavior and emphasizes that content replaces the full document. This is exactly the kind of behavioral context an agent needs for a destructive write operation.

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?

The description is two sentences with no wasted words. It front-loads the core purpose, then adds the essential behavioral details and a practical caution. Every sentence 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 write tool with three simple parameters and no output schema, the description is complete: it states what happens on create vs replace, confirms undoability via snapshots, and warns about preserving unrelated content. Combined with full schema coverage and the destructive hint annotation, an agent has everything needed to invoke it correctly.

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 100%, so the schema already fully explains project_id, path, and content. The description reinforces that content is the 'FULL new content' and that path is created if missing, but it does not add substantial new parameter-level meaning. Baseline of 3 is appropriate.

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 clearly states the action: 'Create or replace a document in one of the user's letX projects.' It then specifies the two cases—existing path replaced, non-existing path created—which precisely distinguishes this from sibling tools like read_project_file or create_project. The verb-plus-resource framing is unambiguous.

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 gives clear operational guidance: 'Prefer reading the file first and preserving everything the user didn't ask to change.' This implies the correct workflow and cautions against overwriting content. It does not explicitly name read_project_file or state 'use this tool when modifying a file,' but the context is clear enough.

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