open-case

name	open-case
description	This skill should be used when the user asks to "open a case", "start an investigation", "investigate this problem", "begin detective mode", or wants to apply structured investigation methodology to solve an unknown-target problem. Initializes a CaseBoard and begins the case-opening phase.

Open Case — Initialize a Detective Investigation

Start a new investigation by creating a CaseBoard and establishing the case foundation with the user.

Process

1. Understand the Problem

Before creating the case, conduct a brief exchange with the user to understand:

• What triggered this investigation (the "crime scene")
• What the desired outcome looks like (can be vague — "find the cause" is valid)
• Any initial clues or suspicions they already have
• Resource constraints (time budget, action limits)

If the user provided a clear problem description as an argument, skip directly to case creation.

2. Create the MCP-backed CaseBoard

For Detective v2/v2.1 cases, create the case through detective_open_case:

detective_open_case(title="<title>", description="<description>", case_id="<case-id>", config={...})

Use a slug derived from the title as <case-id> (e.g., "perf-regression-2026-05"). If the Detective MCP server is unavailable, stop and ask the user to check /mcp.

3. Seed Initial Nodes

Add founding graph nodes through detective_add_node:

• Crime scene: type="observation", source="user", high confidence
• Case goal: type="question" or type="task", source="user", metadata {"is_goal": true}
• Initial clues: type="clue" or type="observation", source="user"
• Initial hypotheses: type="hypothesis", source="user", confidence around 0.5

Connect related founding nodes with detective_add_edge using derives, supports, requires, or related_to as appropriate.

4. Configure Investigation Parameters

Pass case-specific configuration to detective_open_case when creating the case:

• checkpoint_interval: How many actions between user check-ins (default: 5)
• max_actions: Budget limit (default: 50)
• confidence_threshold_confirm: When to confirm a hypothesis (default: 0.85)
• confidence_threshold_eliminate: When to eliminate or down-rank an alternative (default: 0.15)

Adjust based on problem complexity — simple problems: lower max_actions, higher checkpoint frequency.

5. Present the Board

After initialization, display a summary:

• Case title and ID
• Crime scene summary
• Goal statement
• Initial fragments count
• Suggested first investigation direction
• How to proceed (/detective:investigate to start the loop)

Output Format

Present the initialized case to the user in this structure:

## Case Opened: <title>
ID: <case-id>
Phase: Opening

**Crime Scene**: <one-line summary>
**Goal**: <what we're solving>
**Initial Clues**: <count> fragments on board
**Budget**: <max_actions> actions, checkpoint every <interval>

**Suggested First Move**: <what to investigate first>

Run `/detective:investigate` to begin the investigation loop.

State File Location

For v2/v2.1 cases, canonical state is created by detective_open_case at:

.detective/cases/<case-id>/case.json

Do not create or edit case JSON files directly for v2/v2.1 cases.

Legacy v1 fallback resources

Use these only for legacy v1 flat JSON case files when the Detective MCP server is unavailable:

• scripts/board.py — Legacy v1 CaseBoard inspection and deprecated mutation helpers