Nelson

Captain Horatio Nelson — John Francis Rigaud, 1781. Image: Wikimedia Commons

A Claude Code skill for coordinating agent work based on the Royal Navy. It provides structured sailing orders, battle plans, action stations, and a captain's log to manage complex tasks — from single-session work through to parallel subagent squadrons.

What it does

https://github.com/user-attachments/assets/2468679d-39f5-4efb-9d93-43d43eee8907

Nelson gives Claude a six-step operational framework for tackling complex missions:

1. Sailing Orders — Define the outcome, success metric, constraints, and stop criteria
2. Form the Squadron — Choose an execution mode (single-session, subagents, or agent team) and size the team
3. Battle Plan — Split the mission into independent tasks with owners, dependencies, and file ownership
4. Quarterdeck Rhythm — Run checkpoints to track progress, identify blockers, monitor hull integrity, and manage budget
5. Action Stations — Classify tasks by risk tier and enforce verification before marking complete
6. Stand Down — Produce a captain's log with decisions, artifacts, validation evidence, and follow-ups

Prerequisites

• Claude Code CLI installed and authenticated
• Recommended: Enable agent teams for the full squadron experience. Nelson works without it (using single-session or subagent modes), but agent teams unlock teammate-to-teammate coordination — the agent-team execution mode. Enable it in your settings.json:

{
  "env": {
    "CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS": "1"
  }
}

• For split-pane visibility: To see each agent working in its own pane (as shown in the demo video), run Claude Code inside tmux. Agent teams auto-detect tmux and give every teammate a dedicated split pane so you can watch the whole squadron in action.

Installation

Plugin install (recommended)

/plugin install harrymunro/nelson

Or add the marketplace first, then install by name:

/plugin marketplace add harrymunro/nelson
/plugin install nelson@nelson-marketplace

Prompt-based

Open Claude Code and say:

Install skills from https://github.com/harrymunro/nelson

Claude will clone the repo, copy the skill into your project's .claude/skills/ directory, and clean up. To install it globally across all projects, ask Claude to install it to ~/.claude/skills/ instead.

Manual

Clone the repo and copy the skill directory yourself:

# Project-level (recommended for teams)
git clone https://github.com/harrymunro/nelson.git /tmp/nelson
mkdir -p .claude/skills
cp -r /tmp/nelson/skills/nelson .claude/skills/nelson
rm -rf /tmp/nelson

# Or user-level (personal, all projects)
cp -r /tmp/nelson/skills/nelson ~/.claude/skills/nelson

Then commit .claude/skills/nelson/ to version control so your team can use it.

Verify installation

Open Claude Code and ask:

What skills are available?

You should see nelson listed. You can also invoke it directly:

/nelson

Usage

Let Claude invoke it automatically

Claude reads the skill description and loads it when your request matches — for example, when you ask for coordinated parallel work or structured mission execution. Just describe your task:

I need to refactor the authentication system. The work spans the API layer,
the frontend, and the test suite. Use nelson to coordinate this.

Invoke it directly

Use the slash command with your mission brief:

/nelson Migrate the payment processing module from Stripe v2 to v3

Provide structured sailing orders

For maximum control, provide your own sailing orders:

/nelson

Sailing orders:
- Outcome: All API endpoints return consistent error responses
- Success metric: Zero test failures, all error responses match the schema
- Deadline: This session

Constraints:
- Token/time budget: Stay under 50k tokens
- Forbidden actions: Do not modify the database schema

Scope:
- In scope: src/api/ and tests/api/
- Out of scope: Frontend error handling

How it works

HMS Victory anchored off the Isle of Wight — John Wilson Carmichael (1799–1868), National Museum of the Royal Navy, Portsmouth

Execution modes

The skill selects one of three execution modes based on your mission:

Mode	When to use	How it works
single-session	Sequential tasks, low complexity, heavy same-file editing	Claude works through tasks in order within one session
subagents	Parallel tasks where workers only report back to the coordinator	Claude spawns subagents that work independently and return results
agent-team	Parallel tasks where workers need to coordinate with each other	Claude creates an agent team with direct teammate-to-teammate communication

Chain of command

Nelson uses a three-tier hierarchy. The admiral coordinates captains, each captain commands a named ship, and crew members aboard each ship do the specialist work.

                          ┌───────────┐
                          │  Admiral  │
                          └─────┬─────┘
                  ┌─────────────┼─────────────┐
                  ▼             ▼             ▼
           ┌───────────┐ ┌───────────┐ ┌───────────┐
           │  Captain   │ │  Captain   │ │ Red-Cell  │
           │ HMS Daring │ │ HMS Kent   │ │ Navigator │
           └─────┬─────┘ └─────┬─────┘ └───────────┘
            ┌────┼────┐   ┌────┼────┐
            ▼    ▼    ▼   ▼    ▼    ▼
           XO  PWO  MEO  PWO  NO  COX

Squadron level:

• Admiral — Coordinates the mission, delegates tasks, resolves blockers, produces the final synthesis. There is always exactly one.
• Captains — Each commands a named ship. Breaks their task into sub-tasks, crews specialist roles, coordinates crew, and verifies outputs. Implements directly only when the task is atomic. Typically 2-7 per mission.
• Red-cell navigator — Challenges assumptions, validates outputs, and checks rollback readiness. Added for medium/high risk work.

Ship level (crew per captain, 0-4 members):

Role	Abbr	Function	When to crew
Executive Officer	XO	Integration & orchestration	3+ crew or interdependent sub-tasks
Principal Warfare Officer	PWO	Core implementation	Almost always (default doer)
Navigating Officer	NO	Codebase research & exploration	Unfamiliar code, large codebase
Marine Engineering Officer	MEO	Testing & validation	Station 1+ or non-trivial verification
Weapon Engineering Officer	WEO	Config, infrastructure & systems integration	Significant config/infra work
Logistics Officer	LOGO	Documentation & dependency management	Docs as deliverable, dep management
Coxswain	COX	Standards review & quality	Station 1+ with established conventions

NO and COX are read-only — they report findings but never modify files.

Ships are named from real Royal Navy warships, matched roughly to task weight: frigates for general-purpose, destroyers for high-tempo, patrol vessels for small tasks, historic flagships for critical-path, and submarines for research.

Squadron size caps at 10 squadron-level agents (admiral, captains, red-cell navigator). Crew are additional — up to 4 per ship. If a task needs more crew, split it into two ships.

Here's an example of the crew in action: we create four captains. Two of the captains are single-crew (minimum, since captains don't do the work themselves) and two of them are two-crew. So we have 11 agents working together in total:

https://github.com/user-attachments/assets/f3bafd06-790e-44a0-9061-7d1fd666b445

Action stations (risk tiers)

Every task is classified into a risk tier before execution. Higher tiers require more controls:

Station	Name	When	Required controls
0	Patrol	Low blast radius, easy rollback	Basic validation, rollback step
1	Caution	User-visible changes, moderate impact	Independent review, negative test, rollback note
2	Action	Security/compliance/data integrity implications	Red-cell review, failure-mode checklist, go/no-go checkpoint
3	Trafalgar	Irreversible actions, regulated/safety-sensitive	Minimal scope, human confirmation, two-step verification, contingency plan

Tasks at Station 1 and above also run a failure-mode checklist:

• What could fail in production?
• How would we detect it quickly?
• What is the fastest safe rollback?
• What dependency could invalidate this plan?
• What assumption is least certain?

Damage control

Nelson includes procedures for when things go wrong — stuck agents, budget overruns, faulty outputs, and context window exhaustion.

Hull integrity monitoring tracks context window consumption across the squadron. The admiral reads exact token counts from Claude Code session JSONL files at each quarterdeck checkpoint and maintains a squadron readiness board:

Status	Remaining	Action
Green	75–100%	Operating normally
Amber	60–74%	Monitor closely, avoid new work
Red	40–59%	Relief on station — begin handover
Critical	Below 40%	Immediate relief

Relief on station replaces a ship whose context window is depleted. The damaged ship writes a turnover brief to file, a fresh replacement reads it and continues the mission. Chained reliefs (A → B → C) are supported for long-running tasks. The flagship monitors its own hull integrity too and can hand over to a new session.

The token counts come from the API usage data that Claude Code already records on every assistant turn — no estimation heuristics, no paid APIs, no external dependencies. A utility script (scripts/count-tokens.py) extracts the data and produces damage reports.

Other damage control procedures: man overboard (stuck agent replacement), session resumption (picking up after interruption), partial rollback (reverting faulty work), crew overrun (budget recovery), scuttle and reform (mission abort), and escalation (chain of command).

Templates

The skill includes structured templates for consistent output across missions:

• Sailing Orders — Mission definition with outcome, constraints, scope, and stop criteria
• Battle Plan — Task breakdown with owners, dependencies, threat tiers, and validation requirements
• Ship Manifest — Captain's crew plan with ship name, crew roles, sub-tasks, and budget
• Quarterdeck Report — Checkpoint status with progress, blockers, budget tracking, and risk updates
• Damage Report — JSON format for hull integrity reporting with token counts and status
• Turnover Brief — Handover document for relief on station with progress log, running plot, and relief chain
• Red-Cell Review — Adversarial review with challenge summary, checks, and recommendation
• Captain's Log — Final report with delivered artifacts, decisions, validation evidence, and follow-ups

Plugin file structure

.claude-plugin/
├── plugin.json                               # Plugin manifest
└── marketplace.json                          # Marketplace definition (self-hosted)
skills/nelson/
├── SKILL.md                                  # Main skill instructions (entrypoint)
└── references/
    ├── action-stations.md                    # Risk tier definitions and controls
    ├── admiralty-templates/                  # Individual template files
    │   ├── battle-plan.md
    │   ├── captains-log.md
    │   ├── crew-briefing.md
    │   ├── damage-report.md
    │   ├── marine-deployment-brief.md
    │   ├── quarterdeck-report.md
    │   ├── red-cell-review.md
    │   ├── sailing-orders.md
    │   ├── ship-manifest.md
    │   └── turnover-brief.md
    ├── commendations.md                       # Recognition signals and correction guidance
    ├── crew-roles.md                         # Crew role definitions, ship names, sizing
    ├── damage-control/                       # Individual procedure files
    │   ├── crew-overrun.md
    │   ├── escalation.md
    │   ├── hull-integrity.md
    │   ├── man-overboard.md
    │   ├── partial-rollback.md
    │   ├── relief-on-station.md
    │   ├── scuttle-and-reform.md
    │   ├── session-hygiene.md
    │   └── session-resumption.md
    ├── royal-marines.md                      # Royal Marines deployment rules
    ├── squadron-composition.md              # Mode selection and team sizing rules
    └── standing-orders/                      # Individual anti-pattern files
        ├── admiral-at-the-helm.md
        ├── all-hands-on-deck.md
        ├── battalion-ashore.md
        ├── becalmed-fleet.md
        ├── captain-at-the-capstan.md
        ├── crew-without-canvas.md
        ├── drifting-anchorage.md
        ├── press-ganged-navigator.md
        ├── pressed-crew.md
        ├── skeleton-crew.md
        ├── split-keel.md
        └── unclassified-engagement.md
agents/
└── nelson.md                                # Subagent definition
scripts/
└── count-tokens.py                          # Token counter for hull integrity monitoring

• plugin.json declares the plugin name, version, and component paths for Claude Code's plugin system.
• marketplace.json lets users add this repo as a plugin marketplace and install Nelson by name.
• SKILL.md is the entrypoint that Claude reads when the skill is invoked. It defines the six-step workflow and references the supporting files.
• Files in references/ contain detailed guidance that Claude loads on demand — they are not all loaded into context at once.

Customisation

Modify templates

Edit the individual template files in references/admiralty-templates/ to match your team's reporting style. The templates use plain text format — adjust fields, add sections, or remove what you don't need.

Adjust risk tiers

Edit references/action-stations.md to change what controls are required at each station level. For example, you might require red-cell review at Station 1 instead of Station 2 for a security-sensitive project.

Change team sizing

Edit references/squadron-composition.md to adjust the decision matrix or default team sizes.

Compatibility notes

• Subagents are a stable Claude Code feature and work out of the box.
• Agent teams are experimental and disabled by default. See Prerequisites above for setup. Without agent teams enabled, Nelson falls back to single-session or subagents mode. Full details: Agent teams documentation.

Disclaimer

This project is not associated with, endorsed by, or affiliated with the British Royal Navy or the UK Ministry of Defence. All Royal Navy terminology and references are used purely as a creative framework for organising software development tasks.

License

MIT — see LICENSE for details.