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

Beyond the annotations (readOnly, idempotent, closed-world), the description discloses that output is built only from the saved check rather than a live fetch, that every starter is labelled 'Starter, review before publishing', that ARC's own validators check them, and that it never fills in a price. The empty-result condition for ungraded stores is an extra operational behavior an agent would otherwise not expect.

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 artifact inventory is front-loaded in the first sentence and the remaining sentences add constraints rather than restating the name. It is dense but each sentence contributes (source of truth, labelling, read-only scope, empty case); a slightly tighter split into purpose vs. caveats would read better.

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?

There is no output schema, so the description must convey return semantics and does: what files come back, that they are templates labelled for review and validator-checked, and when the result is empty. For a one-parameter, read-only generator, nothing an agent needs to call it correctly 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 the single 'store' param carries its own host-format example, so the schema does the work. The description only adds the cardinality constraint ('one store'), which is marginally useful but not compensating detail. Baseline 3 for a fully documented single parameter.

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 names a specific verb+resource ('Starter files and snippets for the failed Agent Readiness Grade audits of one store') and enumerates the concrete artifacts produced (robots.txt allow rules, UCP profile skeleton, Product JSON-LD, llms.txt). That is distinguishable from siblings like why_blocked_and_fix or validate_ucp_profile, which diagnose or validate rather than emit starters.

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 makes the triggering context clear: this runs off 'ARC's saved check' for a store with failed grade audits, and it states the boundary case that a store with no grade returns no starters. It does not name an alternative (e.g. why_blocked_and_fix) or state an explicit prerequisite such as running precheck first, so routing is inference-based rather than spelled out.

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