Packages, products and add-ons

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered; the description adds real behavioral context beyond that: results are paged, and products/add-ons are silently omitted without a transaction_id (a non-obvious scoping quirk that would otherwise look like an empty result). It stops short of covering auth needs or rate limits, so 4 rather than 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 primary resource and its contents before the conditional transaction branch. The parenthetical endpoint citations add useful anchoring, though the second sentence is dense enough that it takes a second pass to parse.

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 9-parameter read-only listing tool with no output schema, the description covers the essentials: what comes back, how the two modes differ, the paging model, and the transaction scoping constraint. Missing only edge-case behavior (e.g. empty results, ordering), which is minor at this complexity.

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%, so the baseline is 3. The description still adds meaning the schema does not: the schema marks zero required parameters, while the description tells the agent it must supply event_id or performance_id, and it explains the transaction_id dependency that governs whether products/add-ons appear at all.

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 and resource ('Packages ... for one event ... or one performance'), enumerates what the records contain (bundles priced per performance, capacity remaining, total price), and cites the exact endpoints (GET /package/, GET /performance/{id}/package/, GET /product/, GET /add-on/). No sibling tool covers packages or add-ons, so the agent can separate it from list_events/get_transaction without opening the schema.

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 states the selection rule plainly ('Give event_id or performance_id') and explains the transaction branch conditionally: products and add-ons are only fetched when transaction_id is supplied, because the API scopes them to a transaction. That is clear when-to-use guidance, though it never names an alternative sibling tool or a when-not-to-use case.

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