Buildbook/Runbook pairing is a MythOS documentation pattern — a human-facing overview memo paired with one or two agent-executable guides — for packaging a reusable system so a reader and their coding agent can adopt or operate it together.
The overview half, built from the System Overview & Kickoff template, orients a human deciding whether to adopt the system: what it is, why it exists, how its pieces fit together, and when it's worth the setup cost. It pairs with one or both of two execution counterparts, chosen by a litmus test — run the paired document twice in a row: a no-op second run means 📝Buildbook (built from the Agent Buildbook template, converging an environment to a target state once per adopter); new work each run means 📝Runbook (built from the Agent Runbook template, operating a recurring process with a self-improving Run Log and Change Log loop). A system that needs both ships a Buildbook the Runbook's Tooling precondition points at, run automatically the first time — never a separate step the human has to remember.
The overview memo ends with a copy-paste block the reader hands to their own coding agent: retrieve the paired document via MythOS MCP if the agent has it configured, or fetch its public URL directly if not. Both paths return the same complete content, so the pattern works for readers without MythOS at all, while nudging toward MythOS MCP over time — it's the only path that stays current as the documents are revised.
Use the pattern whenever a system is worth someone else replicating, not just reading about — a protocol, a workflow, a piece of tooling. 📝The Git Agent Protocol is the first instance, now with all three pieces: its overview, 📝The Git Agent Protocol — Agent Runbook for the recurring session/release cycle, and 📝Onboarding a Repo to the Git Agent Protocol — Agent Buildbook for one-time repo setup. The three templates — System Overview & Kickoff, Agent Buildbook, and Agent Runbook — carry #instruction-memo and public visibility in the shared template library, ready to reuse for the next system worth packaging this way.
I built this pattern out of a real gap: the Git Agent Protocol's overview memo was good orientation but not runnable by an agent with nothing else. It started as a two-part "Cookbook" pairing; converting the Git Agent Protocol itself exposed that build-once setup and recurring operation are different shapes with different failure modes, which is what split Cookbook into Buildbook and Runbook. The three-piece version is what I actually reach for now.