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

Adds real behavioral context beyond annotations: no credential consumption ("no key") and no effects on certification, reputation, or credit, which is exactly the kind of side-effect disclosure an agent needs and readOnlyHint alone doesn't convey. It stops short of explaining whether the grade is persisted or how it is returned.

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?

A single sentence that leads with the action and packs the key qualifier into a parenthetical, which is efficient. But the compression uses unexplained jargon ("FIX", "no key") that costs more clarity than the brevity saves.

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?

With two required parameters, 0% schema description coverage, no output schema, and a free-form object array as input, the description should describe the answer payload and what grading returns. It covers only the stakes, leaving the agent unable to construct a valid call confidently.

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 0% for both required parameters: "capability" is an unconstrained string and "answers" is an array of untyped objects with no described shape. The description gives no indication of the expected answer format or what values "capability" accepts, so it fails to compensate for the coverage gap.

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?

States a specific verb ("Grade") and resource ("PRACTICE answers"), which distinguishes it from the sibling submit_gym_exam by signalling a non-certifying variant. The unexplained token "FIX" and the terse "no key" phrase keep it from being fully self-explanatory.

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 parenthetical "no key; no certification, reputation or credit effect" implies this is the low-stakes counterpart to submit_gym_exam, so usage is inferable. However, it never explicitly says "use this when you want practice-only grading instead of submit_gym_exam" nor states any prerequisite for calling it.

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