ralph.write_prd

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly says 'write or replace', making the overwrite behavior known, and fixes the file location at .ralph/prd.md. It does not mention formatting, validation, or side effects beyond the file write, but for a single-file write operation this is largely sufficient.

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?

One sentence, no filler, and the most important facts—action, destination, and usage scope—are front-loaded. Every word 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?

The tool is simple: one string parameter, no output schema, and a single target file. The description covers what, where, and when. It is missing only a bit of guidance on how the content should be formatted or how it relates to sibling documents, which is a minor gap at this complexity level.

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?

The only parameter, 'content', has no schema description and the description does not explicitly explain its expected structure beyond the tool's overall purpose. The tool title and phrase 'product requirements document' strongly imply that content is the PRD body, so the meaning is recoverable, but the description adds little explicit semantic detail about format or expectations.

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 names a specific action ('Write or replace'), an exact target ('.ralph/prd.md'), and the document type ('canonical product requirements document'). This clearly distinguishes it from sibling planning and spec tools like write_plan, write_epic_plan, and upsert_spec.

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 phrase 'Used by the Phase 1 Copilot session only' gives a clear context and an explicit restriction on when this tool should be called. It does not name alternative tools or describe what to use in other phases, but the phase-specific scope is strong enough for an agent to route correctly.

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