render_region

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

With only destructiveHint=true declared, the description carries the key behavioral burden and does so well: every invocation fails, and the failure is not recoverable by retrying with different arguments. It doesn't specify the error type or whether anything is written to output_path before failing, which is the only remaining gap. The dead-stub disclosure is far more valuable than the annotation.

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 short sentences, zero waste, with the disqualifying fact front-loaded ahead of the remediation path. Ideal structure for a stub tool.

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 tool that always errors, the description supplies the only things that matter: don't call it, and here is the working path. No output schema is needed since there is no meaningful return. Minor incompleteness only in not clarifying the parameter meanings for anyone debugging a call.

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 0%, so the description must compensate, and it only partially does. The reference to 'the region's start and end from get_regions' implies region_index is an index into that list, but neither parameter is defined, and output_path's meaning (a rendered audio file path? RPP path?) is left to the name 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?

The description immediately states the tool's real behavior ('always returns an error') instead of restating the name, which is exactly what an agent needs to avoid wasting a call. It does not explicitly say 'renders a region', but the routing sentence to render_project conveys the intended function. It is clearly distinguishable from render_project and all other siblings.

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?

It gives an explicit when-not-to-use ('this tool always returns an error') and names the correct alternative plus the supporting call (render_project with start/end from get_regions). The agent knows exactly what to do instead, with no inference needed.

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