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

No annotations are provided, so the description carries the burden. 'Explain' implies a non-mutating read operation, and the alias to POST /api/explain adds a small amount of implementation context. However, it does not disclose return format, error behavior, or whether the operation has any side effects.

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 very concise: two short sentences, each earning its place. The core purpose is front-loaded, and the API alias sentence adds useful implementation context without redundancy.

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 single-parameter explain tool, the description is minimally viable. It identifies the input and the operation, but with no output schema and no annotations, it leaves out what the explanation response looks like and what constraints apply to delta_pct.

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% and the description only names delta_pct without defining its meaning, valid range, or units. The phrase 'for a delta_pct' adds minimal context beyond the schema, and since coverage is 0%, the description should have compensated more.

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 ('Explain'), a specific resource ('the score_v1 rubric grade'), and an input ('delta_pct'). This clearly distinguishes it from its siblings: health is a health check and score_deal is about computing a score, while this tool explains an existing rubric grade.

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 intended use is implied: use this when you need an explanation of a score_v1 rubric grade for a delta_pct. However, it does not explicitly compare itself to score_deal or health, nor does it state when not to use it, so the guidance relies on inference.

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