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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: it is free, requires no license key, defaults to dry-run, and fails closed if the subscription lapses — details an agent cannot get from structured fields.

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?

It is a single dense sentence plus a short pricing/auth tag, with the core purpose front-loaded and no filler. The long parenthetical list of unlocked features is slightly heavy but each clause carries information.

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 zero-parameter, read-only setup endpoint with no output schema, the description covers what the returned content contains (connection steps, entitlements, key handling, cadence, lapse behavior) and its cost/auth requirements. It could be marginally more complete by stating that the response is human/agent-readable guidance and by explicitly positioning this as the prerequisite call.

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?

The tool takes zero parameters, so the baseline is 4. The description correctly adds no parameter semantics because none are needed, and it does not mislead about inputs.

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 resource — the setup/onboarding information for connecting to Coil Live — and enumerates what it covers (subscription entitlements, license key transmission, polling cadence, fail-closed behavior). It is distinguishable from siblings by being a meta/onboarding endpoint rather than a data feed, though the mention of 'the live rulebook' brushes against the get_live_rules sibling without clarifying the difference.

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?

'starts in dry-run' and 'Free; no key needed' imply this is the entry point an unauthenticated agent should call first, but the description never explicitly says 'call this before other live tools' or names an alternative. Usage is inferred rather than stated.

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