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

With zero annotations the description carries the full burden, and it delivers: cost (0.10 USDC), automatic payment via the BRIJ wallet, and a specific error contract (409 identity_documents_not_supported with the condition that triggers it). It omits idempotency/duplicate-intent behavior and any expiry on the intent, which is material for a paid escrow mutation.

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?

Front-loaded with the action, cost, and sequencing. The final 409 sentence is long but earns its place by explaining the edge case that only fires outside the normal search flow.

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?

Complete for the task: sequencing, cost, payment source, downstream handoff, and the failure mode are all covered, and an output schema already documents the return values so the description need not expand on them.

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%, including wallet defaults, so the baseline is 3. The description adds no syntax or format detail for offer_id or the wallet params beyond what the schema already states.

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 + resource ('Reserve an escrow booking intent for a flight offer') and distinguishes itself from travel_search_flights and travel_book_flight by naming both siblings and its position between them.

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?

Explicitly states when to call ('AFTER travel_search_flights and the user has picked an offer') and what to do with the result (pass into travel_book_flight). It does not name a true alternative tool or an explicit when-not-to-use case, so it falls just short of a 5.

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