Full details for one car by its id (from search_cars), including photos, dealer contact and whether it has sold.
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"id": "<id>"
},
"name": "get_car"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description must carry the load; it discloses the return payload (photos, dealer contact, sold flag), which is the key behavioral fact since there is no output schema. It omits edge behavior such as what happens for an invalid id or a removed listing, keeping it below 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?
A single front-loaded sentence with the scope, the input source, and the return contents — no filler or redundancy.
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 one-parameter read tool with no output schema and no annotations, the description covers the essential scope, input provenance, and return contents. Only failure/error behavior for a missing or sold car is 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 0% and the only parameter is an untyped-in-description string 'id'. The description helpfully notes the id originates from search_cars, but gives no format, length, or validity guidance beyond that provenance hint.
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 and resource — 'Full details for one car by its id' — and enumerates what 'details' includes (photos, dealer contact, sold status). It is clearly distinguishable from search_cars (bulk lookup), list_dealerships and out_the_door_price.
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 parenthetical '(from search_cars)' signals the intended workflow: find cars with search_cars, then fetch one by id. There is no explicit statement of when not to use it or what to do with an unknown id, but the routing context is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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