Answer a step in a run

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

With no annotations, the description carries the full burden of explaining behavior. It usefully discloses that na never counts as passed, that re-answering overwrites the previous answer, and that the run must be open. However, it omits the pending state allowed by the schema and says nothing about effects on run status or sign-off, leaving some behavioral ambiguity.

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 sentences with no filler. The first sentence states the core action, and the following sentences add only essential edge-case semantics. The structure is front-loaded and 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?

The tool is simple, the schema fully documents its parameters, and the description clarifies the most important behavioral nuances. The only notable gap is the absence of a mention of the pending reset state and any return/confirmation behavior, but these are minor for this operation.

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 documents all six parameters, including defaults, formats, and examples. The description adds prose around na semantics and the who/when intent, but does not need to compensate for missing parameter documentation.

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 uses a specific verb ('Mark') with a specific resource ('one step') and the exact allowed outcomes (pass, fail, na). This clearly distinguishes run_check from run-level sibling tools like run_sign_off, run_status, and run_report.

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 context: this tool records step-level answers, can be used again while the run is open, and the latest answer is the effective one. It does not explicitly name alternative sibling tools or state when not to use it, so it stops short of a 5.

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