Branchwright MCP

roll_check

Idempotent

Records a server-resolved d20 check with fixed purpose, difficulty, and stakes, preventing rerolls and returning the full check set plus context hash for persistent adventures.

Instructions

Persist a server d20 result with fixed purpose, difficulty and stakes. No rerolling a purpose. Returns the complete check set and context hash.

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": {
      "campaign_id": "<campaign_id>",
      "branch_id": "<branch_id>",
      "preparation_id": "<preparation_id>",
      "check_id": "<check_id>",
      "purpose": "<purpose>",
      "attribute": "<attribute>",
      "difficulty": "<difficulty>",
      "stakes": "<stakes>"
    },
    "name": "roll_check"
  }
}

Input Schema

Name	Required	Description	Default
`basis`	No
`stakes`	Yes
`purpose`	Yes
`check_id`	Yes
`attribute`	Yes
`branch_id`	Yes
`difficulty`	Yes
`campaign_id`	Yes
`situational`	No
`preparation_id`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Oct 18, 2026

TDQS

B3.2/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false. The description adds real context beyond them: that purpose/difficulty/stakes are fixed, that a purpose cannot be rerolled, and that the complete check set plus a context hash are returned. That is useful behavioral detail for a persistence tool.

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

Conciseness4/5

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

Three tight sentences with the core action front-loaded, followed by the immutability rule and the return summary. No wasted words, though the sentences are terse to the point of under-explaining the missing parameters.

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

Completeness3/5

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

For a 10-parameter mutation tool with no output schema, the description helpfully summarizes the return value. However, it is far too thin for the parameter surface, leaving most required fields unexplained, so an agent cannot call it correctly from the definition alone.

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

Parameters2/5

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

Schema description coverage is 0% across 10 parameters (8 required), so the description carries the full burden. It names only purpose, difficulty and stakes, leaving campaign_id, branch_id, preparation_id, check_id, attribute, basis and situational 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.

Purpose4/5

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

States a specific verb and resource: 'Persist a server d20 result' with the fixed attributes (purpose, difficulty, stakes). It is clear what the tool does, though it does not explicitly differentiate itself from siblings like preview_world or get_state.

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

Usage Guidelines2/5

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

Offers only a single constraint ('No rerolling a purpose') rather than guidance on when to call this versus alternatives. There is no mention of prerequisites (e.g., needing a preparation or branch first) or when-not-to-use, leaving usage to inference.

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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