Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add commands/coleam00/context-engineering-intro/prime-backendgit clone --depth 1 https://github.com/coleam00/context-engineering-introWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/commands/coleam00/context-engineering-intro/prime-backend)<a href="https://agentmods.dev/commands/coleam00/context-engineering-intro/prime-backend"><img src="https://agentmods.dev/badge/commands/coleam00/context-engineering-intro/prime-backend.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00012 | $0.00756 |
| Opus 5 | $0.00006 | $0.00378 |
| Sonnet 5 | $0.00002 | $0.00151 |
| Haiku 4.5 | $0.00001 | $0.00076 |
Grade A, and why
prime-backend scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
91% identical to prime-backend — 16 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Prime Backend: Core and Server Orientation
Objective
Orient on the backend packages (packages/core/ and packages/server/) before working on
server logic, orchestration, AI clients, slash commands, or API routes.
Process
1. Understand the Core Package Structure
!ls packages/core/src/
2. Understand Message Flow (Orchestrator)
Read packages/core/src/orchestrator/orchestrator-agent.ts — the single entry point for all
platform messages. Maps messages to slash commands (via command-handler) or AI execution. Note
the lazy logger pattern and MAX_BATCH constants.
Read packages/core/src/orchestrator/orchestrator.ts first 60 lines — validateAndResolveIsolation
and dispatchBackgroundWorkflow utilities called by orchestrator-agent.
Read packages/core/src/orchestrator/prompt-builder.ts first 40 lines — how system prompts
are assembled with codebase context.
3. Understand Slash Command Routing
Read packages/core/src/handlers/command-handler.ts first 80 lines — deterministic command
dispatch (no AI). Note the full list of supported slash commands.
4. Understand Session State Machine
Read packages/core/src/state/session-transitions.ts in full — TransitionTrigger union type,
TRIGGER_BEHAVIOR record (creates / deactivates / none), and session lifecycle rules.
5. Understand AI Client Patterns
List clients:
!ls packages/core/src/clients/
Read packages/core/src/clients/factory.ts for provider selection logic.
Read packages/core/src/clients/claude.ts first 50 lines — IAssistantClient implementation
with streaming event loop pattern.
6. Understand Database Layer
List DB modules:
!ls packages/core/src/db/
Read packages/core/src/types/index.ts (or the main types file) first 60 lines for key
interfaces: IPlatformAdapter, IAssistantClient, Conversation, Session.
7. Understand the Server
Read packages/server/src/index.ts first 80 lines — adapter wiring, port allocation logic
(worktree auto-port in 3190–4089 range), Hono app setup.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 97 lines · 12 tokens per session scan A 3ff1e4201f62
prime-backend is a command published in the GitHub repository coleam00/context-engineering-intro (13,822 stars, last pushed 5mo ago), licensed MIT. It adds 12 tokens to every session and 756 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to prime-backend, differing in 16 lines, and is treated as a copy.
Other commands, from other repositories
git
Git operations with intelligent commit messages and workflow optimization.
checklist
Generate a custom checklist for the current feature based on user requirements.
clarify
Identify underspecified areas in the current feature spec by asking up to 5 highly targeted clarification questions and encoding answers back into the spec.
specify
Create or update the feature specification from a natural language feature description.
analyze
Perform a non-destructive cross-artifact consistency and quality analysis across spec.md, plan.md, and tasks.md after task generation.
converge
Assess the current codebase against the feature's spec, plan, and tasks, then append any remaining unbuilt work as new tasks to tasks.md so implement can complete it.