Nelson

Squadron-scale agent coordination for Claude Code — with risk tiers, damage control, and decision logs.

A Claude Code skill that organises multi-agent work into structured naval operations: sailing orders define the mission, captains command parallel workstreams, action stations enforce risk-appropriate controls, and a captain's log captures every decision for audit.

4 risk tiers · 10 damage control procedures · 10 mission templates · 7 crew roles · 15 standing orders

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

Contents

• Quick Start
• What it does
• Why Nelson?
• How it works
• Prerequisites
• Installation
• Usage
• Customisation
• Plugin file structure
• Mission artifacts
• Compatibility notes
• Star History
• Disclaimer
• License

Quick Start

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

Then just describe your mission:

Use Nelson to migrate the payment module from Stripe v2 to v3

Nelson is a Claude Code skill — it loads automatically when your request matches. No slash command needed. See Prerequisites for the full agent-team experience with split panes.

What it does

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

Nelson gives Claude an eight-step operational framework for tackling complex missions:

1. Sailing Orders — Define the outcome, success metric, constraints, and stop criteria
2. The Estimate — Conduct the 7 Question Maritime Tactical Estimate: reconnaissance, intent, effects, terrain, forces, coordination, and control
3. Battle Plan — Turn approved effects into task assignments with owners, dependencies, and file ownership
4. Form the Squadron — Choose an execution mode (single-session, subagents, or agent team) and size the team
5. Get Permission to Sail — Present the plan for user approval before committing resources
6. Quarterdeck Rhythm — Run checkpoints to track progress, identify blockers, monitor hull integrity, and manage budget
7. Action Stations — Classify tasks by risk tier and enforce verification before marking complete
8. Stand Down — Produce a captain's log with decisions, artifacts, validation evidence, and follow-ups

Why Nelson?

Most agent orchestration tools focus on starting missions. Nelson focuses on completing them safely.

Nelson gives your missions a shared vocabulary: "action stations" instead of "risk tier escalation", "hull integrity" instead of "context window consumption", "man overboard" instead of "stuck agent replacement". The names stick. So do the habits.

• Risk-gated execution — Four station tiers (Patrol through Trafalgar) classify every task before it runs. High-risk work requires human confirmation; low-risk work flows without ceremony.
• Damage control built in — Ten named procedures for stuck agents, context exhaustion, faulty output, budget overruns, and mission abort. These are protocols, not improvisation.
• A decision log by default — Captain's log, quarterdeck reports, and turnover briefs are written as the mission runs. Every decision is auditable after the session ends.

Nelson coordinates its own development — recent releases have been planned and executed as Nelson missions.

Who is this for?

• You run Claude Code missions spanning multiple files or modules in parallel
• You want structured checkpoints, risk classification, and a decision log
• You've lost work to context exhaustion and want systematic handover procedures
• You care about auditability — knowing what was decided, by which agent, and why

It may be overkill if you're doing a quick, single-file edit.

How Nelson compares

Both rapid-execution frameworks and Nelson's structured approach are useful — they optimise for different constraints.

If you need fast parallel execution with minimal ceremony, OmO or RuFlo may suit you better. If coordination, auditability, and safe scaling matter more than raw tempo, Nelson is the better fit.

How it works

Execution modes

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

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. Coordinates final synthesis but does not perform it directly. 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):

Navigating Officer (NO) and Coxswain (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:

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

Most agent frameworks assume the happy path. Nelson includes battle-tested procedures for when things go wrong — stuck agents, budget overruns, faulty outputs, and context window exhaustion all have documented recovery paths.

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:

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).

Conflict radar

When multiple ships work in parallel, undeclared file overlaps are a common source of merge pain. Nelson ships two tools that catch conflicts at different stages:

• Pre-flight conflict scan (nelson_conflict_scan.py) — parses the battle plan before Action Stations, walks the codebase import graph, and flags "split-keel" violations where two captains own files that import each other.
• Runtime conflict radar (nelson_conflict_radar.py) — compares live git status against the battle plan's file ownership declarations during execution and alerts on changed files that have no registered owner.

Both tools are stdlib-only and run as part of the mission workflow without additional setup.

Enforcement hooks

Nelson is not purely advisory. A set of Claude Code hooks (hooks/nelson_hooks.py) enforce structural guarantees at the tool level:

Plugin installs auto-discover hooks/hooks.json and wire these up with no user action. Hooks degrade gracefully: if no active Nelson mission is found, they exit cleanly and do not interfere with non-Nelson workflows. See Installation for manual-install caveats.

Cross-mission intelligence

Nelson accumulates learning across missions in .nelson/memory/. Each completed mission feeds a persistent pattern library (patterns.json) and standing-order violation stats (standing-order-stats.json). Four nelson-data.py subcommands expose this:

• brief — pre-mission intelligence brief: relevant patterns, win rate, standing order hot spots, and context-matched precedents drawn from prior missions.
• analytics — focused metric queries (success-rate, standing-orders, efficiency) with text or JSON output.
• history / index — review and rebuild the fleet intelligence index across past missions.
• stand-down --adopt/--avoid — capture reusable patterns at mission close so the next run benefits.

Running index backfills the memory store for missions completed before the feature existed, so upgrading is non-destructive.

Admiral synthesis

Once every ship has reported on Stand Down, the admiral produces a fleet-wide synthesis — consolidating captain outputs into a single decision record. Boundary controls prevent premature synthesis (before all ships have reported) and keep the admiral out of direct implementation.

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

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. Plugin installs ship a settings.json that enables this automatically. For manual installs, add this to 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)

Add the marketplace and install:

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

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

# 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

/plugin marketplace update nelson-marketplace
/plugin install nelson@nelson-marketplace

What skills are available?

cd ~/.cursor/plugins/local
git clone -b main --depth 1 https://github.com/harrymunro/nelson.git

cd ~/.cursor/plugins/local/nelson
git pull

Usage

Nelson is a Claude Code skill — it loads automatically when your request matches. No slash command required. Just describe your mission and mention Nelson.

Let Nelson pick the execution mode

Nelson selects the best execution mode (single-session, subagents, or agent team) based on your mission:

Use Nelson to migrate the payment processing module from Stripe v2 to v3

Force an agent team

If you want teammate-to-teammate coordination, ask for an agent team explicitly:

Use an agent team with Nelson to refactor the authentication system across
the API layer, frontend, and test suite

Go maximal

For the highest-capability run — Opus 4.6 agents, fully crewed ships, maximum coordination:

Use an agent team with Nelson and Opus 4.6 agents with fully crewed ships
to deliver the new billing integration

Full sailing orders

For maximum control, provide your own sailing orders:

Use Nelson to deliver this:

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

You can also invoke it directly with the /nelson slash command if you prefer.

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.

Plugin file structure

.claude-plugin/           # Plugin + marketplace manifests
settings.json             # Default settings (enables agent teams)
hooks/                    # Enforcement hooks (auto-discovered by plugin)
skills/nelson/
├── SKILL.md              # Main skill instructions (entrypoint)
├── references/           # Supporting docs loaded on demand
│   ├── action-stations.md        # Risk tier definitions
│   ├── admiralty-templates/      # 10 structured templates
│   ├── crew-roles.md             # Crew role definitions & ship names
│   ├── damage-control/           # 10 recovery procedures
│   ├── standing-orders/          # 15 anti-pattern guards
│   └── squadron-composition.md   # Mode selection & team sizing
└── scripts/              # nelson-data.py, conflict scan, tests

.claude-plugin/
├── plugin.json                               # Plugin manifest
└── marketplace.json                          # Marketplace definition (self-hosted)
settings.json                                 # Plugin default settings (enables agent teams)
hooks/
├── hooks.json                                # Skill-scoped hook configuration (auto-discovered)
├── nelson_hooks.py                           # Hook enforcement script (preflight, brief, task, idle)
└── test_nelson_hooks.py                      # Tests for hook handlers
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
│   │   ├── comms-failure.md
│   │   ├── 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
│   ├── model-selection.md                    # Cost-optimized model assignment for agents
│   ├── royal-marines.md                      # Royal Marines deployment rules
│   ├── squadron-composition.md               # Mode selection and team sizing rules
│   ├── structured-data.md                    # Structured fleet data capture reference
│   ├── tool-mapping.md                       # Nelson-to-Claude Code tool reference
│   └── standing-orders/                      # Individual anti-pattern files
│       ├── admiral-at-the-helm.md
│       ├── all-hands-on-deck.md
│       ├── awaiting-admiralty.md
│       ├── battalion-ashore.md
│       ├── becalmed-fleet.md
│       ├── captain-at-the-capstan.md
│       ├── crew-without-canvas.md
│       ├── drifting-anchorage.md
│       ├── light-squadron.md
│       ├── paid-off.md
│       ├── press-ganged-navigator.md
│       ├── pressed-crew.md
│       ├── skeleton-crew.md
│       ├── split-keel.md
│       └── unclassified-engagement.md
└── scripts/                                  # Distributed with the skill (since v1.9.1)
    ├── nelson-data.py                        # CLI entry point for structured data capture
    ├── nelson_data_utils.py                  # Shared I/O, validation, constants
    ├── nelson_data_memory.py                 # Cross-mission memory store (v2.0.0)
    ├── nelson_data_lifecycle.py              # Mission lifecycle commands
    ├── nelson_data_fleet.py                  # Fleet intelligence & analytics
    ├── nelson_conflict_scan.py               # Pre-flight split-keel scanner
    ├── nelson_conflict_radar.py              # Runtime file-conflict monitor
    ├── nelson-phase.py                       # Deterministic phase engine
    └── test_*.py                             # Test suite (pytest)
agents/
└── nelson.md                                 # Agent definition with skill binding
scripts/
├── check-references.sh                       # Cross-reference validation for documentation links
└── 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 eight-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.
• hooks/hooks.json is auto-discovered by the Claude Code plugin system; the commands resolve via ${CLAUDE_PLUGIN_ROOT} and only run when Nelson is installed as a plugin.
• skills/nelson/scripts/ ships nelson-data.py and its sibling modules (including the conflict radar and pre-flight conflict scanner) alongside the skill so they are distributed on install. The root-level scripts/ directory holds repo-level utilities (count-tokens.py, check-references.sh).

Mission artifacts

Each mission creates a timestamped directory for its runtime artifacts. Previous missions are preserved — each run gets its own directory. The SESSION_ID suffix is an 8-character hex string generated at session start via uuidgen, ensuring concurrent Nelson sessions in the same repository create distinct directories.

Nelson writes two kinds of artifacts side by side: prose for humans (captain's log, quarterdeck report, turnover briefs) and structured JSON for machines (session resumption, hooks, analytics). The JSON files are produced by nelson-data.py subcommands called at each workflow step.

.nelson/
├── missions/{YYYY-MM-DD_HHMMSS}_{SESSION_ID}/
│   ├── captains-log.md         — Written at stand-down
│   ├── quarterdeck-report.md   — Updated at every checkpoint
│   ├── damage-reports/         — Ship damage reports (JSON)
│   ├── turnover-briefs/        — Ship turnover briefs (markdown)
│   ├── sailing-orders.json     — Mission definition (init)
│   ├── battle-plan.json        — Tasks, owners, file ownership (plan-approved)
│   ├── mission-log.json        — Event stream (events, handoffs, checkpoints)
│   ├── fleet-status.json       — Current squadron state (live)
│   └── stand-down.json         — Final outcome, decisions, adopted/avoided patterns
└── memory/                     — Cross-mission memory store (v2.0.0)
    ├── patterns.json           — Accumulated adopt/avoid pattern library
    └── standing-order-stats.json — Violation frequency & correlations

Compatibility notes

Platform support

Nelson requires agent-team coordination primitives — shared task lists, peer messaging between agents, and team lifecycle management. These are the foundation of Nelson's squadron model: captains coordinating in parallel, the admiral running quarterdeck checkpoints, and damage control procedures that depend on live communication between agents.

Why not degrade gracefully? Nelson's value is the coordination layer — quarterdeck rhythm, peer messaging, shared task lists, damage control, crew hierarchy. On a platform without agent teams, Nelson would degrade to "subagents with Royal Navy naming", which doesn't justify the complexity. When these platforms add agent-team support, Nelson will follow.

We are actively tracking multi-agent developments across these platforms. If you're interested in helping bring Nelson to a new platform, open an issue.

Claude Code specifics

• 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.

Star History

Get started

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

Then just say "Use Nelson to..." and describe your mission, or open an issue if something breaks.

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.