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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds real context beyond that: the exact field set returned and the semantics of the not_charged status ('nothing settled'), which an agent cannot get from structured fields. It omits not-found/error behavior, which keeps it from a 5.

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?

Two sentences, front-loaded with the resource and scope, then the returned fields, then the one status caveat. Every clause carries information; nothing is redundant with the title or schema.

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?

With no output schema, the description correctly compensates by naming the fields returned, and it explains the one non-obvious status value. For a single-parameter idempotent lookup it is essentially complete, with only failure/empty-result behavior left unspecified.

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 coverage is 100% and the single parameter already documents both the id and the tolla.network/r/<id> link alternative, so the baseline is 3. The description adds the '24 hex characters' constraint not present in the schema, which is a genuine but modest increment.

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 concrete verb and resource ('One TOLLA toll receipt by id') and enumerates the returned fields (booth, payer/payee, USDG amount, settlement tx, explorer link), so the agent knows exactly what it gets back. It does not name sibling tools, but none of the listed siblings (list_booths, network_stats, search_lanes) plausibly overlaps a single-receipt lookup, so differentiation is implicit rather than stated.

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?

Usage is implied by the id requirement and the accepted tolla.network/r/<id> link form, which tells the agent the accepted input shape. There is no explicit when-to-use/when-not guidance or mention of what to do when a receipt is missing; the caller must infer that this is the single-record fetch path.

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