from fastmcp import FastMCP
from mcptree import DecisionTrees

mcp = FastMCP("incident-bot")
DecisionTrees(mcp, "trees/")   # mounts tools, sessions, audit trail

pip install -e .
mcptree serve trees/

mcptree validate trees/       # lint trees in CI — node-level errors
mcptree viz trees/incident.yaml   # render a tree as a mermaid diagram

mcptree: "0.1"
id: incident-triage
title: Production incident triage
entry: check_health

nodes:
  check_health:
    type: action                    # instruct the agent to call a tool it has
    tool: http_get
    args: { url: "https://api.example.com/health" }
    result: { capture: health }     # reported result stored into session facts
    next: branch_on_status

  branch_on_status:
    type: condition                 # pure data branch — engine-evaluated, no round trip
    on: health.status               # fact path
    branches:
      - when: { eq: 200 }
        then: all_clear
      - when: { gte: 500 }
        then: inspect_logs
    default: ask_maintenance        # v0.1: every condition node requires a default

  classify_error:
    type: judgment                  # the ONLY place the model decides, and only among declared options
    prompt: Classify the dominant error in the logs.
    evidence: [logs]
    options:
      - { id: oom,     then: remediate_oom }
      - { id: db_conn, then: remediate_db }
      - { id: unknown, then: escalate }
    require_rationale: true         # rationale recorded in the trace

  all_clear:
    type: terminal
    outcome: resolved
    summary: "Service healthy; no action required."

  # ... inspect_logs, ask_maintenance, remediate_oom, remediate_db, escalate
  # in trees/incident.yaml

flowchart TD
  check_health["check_health<br/>action: http_get"]
  branch_on_status{"branch_on_status<br/>on health.status"}
  inspect_logs["inspect_logs<br/>action: get_logs"]
  classify_error[["classify_error<br/>judgment"]]
  ask_maintenance["ask_maintenance<br/>ask"]
  all_clear(["all_clear<br/>resolved"])
  remediate_oom(["remediate_oom<br/>remediate"])
  remediate_db(["remediate_db<br/>remediate"])
  escalate(["escalate<br/>escalate"])
  check_health --> branch_on_status
  branch_on_status -- eq 200 --> all_clear
  branch_on_status -- gte 500 --> inspect_logs
  branch_on_status -- default --> ask_maintenance
  inspect_logs --> classify_error
  classify_error -- oom --> remediate_oom
  classify_error -- db_conn --> remediate_db
  classify_error -- unknown --> escalate
  ask_maintenance -- yes --> all_clear
  ask_maintenance -- no --> escalate

{
  "session_id": "ses_23d02c087aca",
  "tree_id": "incident-triage",
  "node": "check_health",
  "step": 1,
  "error": null,
  "outcome": null,
  "evidence": {},
  "state": "awaiting_tool_result",
  "instruction": "Call tool `http_get` with the args in `expects.args`, then report its result via tree_answer (set is_error=true if the call failed).",
  "expects": {
    "kind": "tool_result",
    "tool": "http_get",
    "args": { "url": "https://api.example.com/health" },
    "schema": null
  }
}

{
  "session_id": "ses_23d02c087aca",
  "tree_id": "incident-triage",
  "node": "inspect_logs",
  "step": 2,
  "error": null,
  "outcome": null,
  "evidence": {},
  "state": "awaiting_tool_result",
  "instruction": "Call tool `get_logs` with the args in `expects.args`, then report its result via tree_answer (set is_error=true if the call failed).",
  "expects": {
    "kind": "tool_result",
    "tool": "get_logs",
    "args": { "service": "api", "lines": 200 },
    "schema": null
  }
}

{
  "session_id": "ses_23d02c087aca",
  "tree_id": "incident-triage",
  "node": "classify_error",
  "step": 3,
  "error": null,
  "outcome": null,
  "evidence": { "logs": { "lines": ["java.lang.OutOfMemoryError: heap"] } },
  "state": "awaiting_judgment",
  "instruction": "Classify the dominant error in the logs.",
  "expects": {
    "kind": "enum",
    "options": ["oom", "db_conn", "unknown"],
    "require_rationale": true
  }
}