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

Beyond the annotations (which only say the tool is not read-only, not idempotent, not destructive), the description discloses useful behavioral constraints: replies only work on the caller's submissions, the original report cannot be edited, and closed submissions reject replies. This gives the agent realistic expectations about side effects and failure conditions.

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 short and front-loaded: the core action appears in the first sentence, followed by parameter guidance and constraints in the next two sentences. Every sentence adds value, with no fluff or repetition of the title.

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 three-parameter mutation tool with a full schema and an output schema present, the description covers the essential context: what the tool does, who can use it, what parameters matter, how attachments relate to another tool, and the key edge case (closed submissions). Nothing critical is missing.

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%, and each parameter already has a meaningful description in the schema. The tool description adds a little context by tying attachments to upload_submission_screenshot and emphasizing the text/attachment pairing, but does not significantly go beyond what the schema already documents. Baseline 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 states a specific verb ('Post a reply') and resource ('one of the calling user's submissions'), and includes a concrete motivating example ('answer a clarification question from Embers'). This clearly distinguishes it from sibling tools like create_submission or get_submission.

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 usage context: reply to a submission, optionally attach screenshots, and notes that a closed submission takes no replies. It also clarifies a limitation ('The original report cannot be edited'). It does not explicitly name alternative tools for when to use something else, but the guidance is sufficient for the primary workflow.

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