openactors

Fetch Actor details

fetch-actor-details

Retrieve an Actor's full input JSON Schema and description to know required fields and parameter names before calling it. Avoids faulty calls by clarifying the expected input structure.

Instructions

Get the full JSON Schema for an Actor's input, plus its description. Call this before call-actor so you know which fields are required and how they are named.

Tool call template

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": {
      "actor": "<actor>"
    },
    "name": "fetch-actor-details"
  }
}

Input Schema

Name	Required	Description	Default
`actor`	Yes	Actor id, e.g. "jobs/ats-boards".

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 5, 2026

TDQS

A4/5.0

Behavior3/5

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

With no annotations present, the description carries the full burden of behavioral disclosure. It conveys a read operation ('Get') and describes the return value, but it does not explicitly state that the operation is side-effect-free, mention auth requirements, or outline error behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, each earning its place: the first defines what the tool returns, the second gives actionable sequencing advice. There is no redundant or filler content.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter introspection tool, the description covers what is returned and the correct moment to call it. The lack of an output schema is compensated by the description naming the return contents. Minor gaps around side-effects and errors do not materially impair an agent's ability to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The sole parameter is fully documented in the input schema ('Actor id, e.g. "jobs/ats-boards"'), and schema description coverage is 100%. The description adds no new meaning to the parameter, so it sits at the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Get') and a precise resource ('the full JSON Schema for an Actor's input, plus its description'). It also differentiates itself from the sibling call-actor by positioning itself as the necessary precursor.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says 'Call this before call-actor so you know which fields are required and how they are named,' giving clear when-to-use guidance with a rationale. It does not, however, name conditions where this tool should not be used or point to alternatives beyond call-actor.

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