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

Beyond the readOnly/idempotent annotations, the description discloses default-expansion behavior (include_components defaults true, and results are tagged with via_product so the agent can tell which product a component-org belongs to). It also gives crucial negative-result semantics: suppliers appear only where a source states them, so an empty row means "not stated," not "no supplier" — exactly the kind of trait annotations cannot carry.

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 core purpose, then the component-expansion behavior, then the data-quality caveat — a sensible ordering. It is a long, dense, run-on construction with stacked clauses that could be split for readability, but no sentence is filler.

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 carries the return-shape burden and does so: it names the fields (relation, role, relation status, quote, source, via_product). For a two-parameter, read-only lookup whose annotations already establish safety, nothing material needed to call it correctly is missing.

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%, so the baseline is 3, but the description adds real meaning: it shows the semantic shape of a component-inclusive result (via_product naming the engine) and enumerates the relation vocabulary the agent should expect. The product parameter is only implicitly covered as an id/title/alias lookup, which 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?

The description states a specific verb and resource — the organizations behind one product — and enumerates what each row carries (relation type such as produced_by_org/supplied_by/operated_by, role, relation status, quote, source). The explicit list of who can appear (makers, agencies, prime contractors, suppliers of named parts, operators) distinguishes it from direction-reversed siblings like products_by_maker without needing 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?

Usage is grounded in a concrete worked example ("who makes the engines used on Vulcan Centaur"), and the default-on include_components behavior is explained so the agent knows the call already covers component products. It does not, however, name alternatives or state when-not to use it, so the routing versus products_by_maker or product_parts is left implicit.

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