Your calls of priced tools, newest first; tool ("titles", ...) narrows. Same as GET /v1/calls. Free.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "list_calls"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| tool | No | ||
| limit | No | ||
| api_key | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations, so the description carries the full burden. It does disclose ordering (newest first), that results are limited to the caller's own calls, and that the call is "Free" (no credit cost) — genuinely useful behavioral facts. It omits pagination behavior, whether default limit truncates, and auth requirements for api_key.
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?
Extremely compact and front-loaded — scope, ordering, filter, and REST mapping packed into one telegraphic sentence with no filler. Density borders on clipped ("narrows" is elliptical), but nothing is wasted.
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?
Output schema exists so return values needn't be described, and the description covers scope/ordering/cost. But with zero annotation and zero schema-description coverage, gaps around limit/paging and authentication leave an agent without enough to invoke confidently.
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% across 3 params. The description only explains `tool`, giving an example value ("titles") not present in the schema; `limit` and `api_key` are left entirely undocumented in both schema and description.
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 ("Your calls of priced tools") with ordering ("newest first"), and the possessive plus plural distinguishes it from the sibling get_call. The phrase "calls of priced tools" is slightly opaque but an agent can tell this is a list endpoint.
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?
Implies usage via "tool ("titles", ...) narrows", showing the filter narrows results to a given tool, but never states when to use this versus get_call or list_runs. The REST equivalence ("Same as GET /v1/calls") helps map to known API docs but is not an explicit use condition.
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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