Book a ClickBus ticket (gated)

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

Annotations already indicate a destructive, non-readonly write operation. The description adds useful behavioral context: it fails closed, requires an environment flag, requires explicit user intent, and guest tokens cannot charge. It does not describe what happens after a successful booking, but the annotations plus the gating notes cover the most important behavioral risks.

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?

Four short, front-loaded sentences with no filler. 'Fail-closed' immediately communicates the most critical behavioral constraint, and every subsequent sentence adds distinct gating or auth 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 mutation tool with six parameters, no output schema, and financial implications, the description is incomplete. It fully covers gating requirements but omits how to obtain trip_id, what the response contains, and what a successful booking actually does. An agent would still need significant external knowledge to call this correctly.

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 only 17%, and the description does not compensate. Only explicit_user_intent is referenced, while from, to, departure_date, trip_id, and response_format are left entirely undocumented. The description reinforces the intent flag but adds nothing about required travel parameters or the output format.

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 title clearly states the operation: 'Book a ClickBus ticket (gated)', and the name 'clickbus_book' matches. The description itself does not restate the purpose, instead focusing on gating requirements, but the tool is still unambiguous and distinct from sibling search/cancel tools.

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 explicitly names prerequisites: CLICKBUS_ALLOW_MUTATIONS and explicit_user_intent, and warns that guest tokens cannot charge. It also says 'Default examples never enable this,' which tells agents not to invoke it casually. It does not explicitly say 'use after search_trips' or contrast with alternatives, but the gating guidance is clear.

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