What Makes an Agency Relationship Actually Work

I’ve sat on both sides of the agency relationship — managing external agencies as a client, and, through Onemarc, running the agency side of that relationship for other businesses. The pattern that stands out from both seats is how rarely a failed engagement comes down to a lack of skill. Almost always, it comes down to a handful of structural issues, and most of them are visible within the first month, if someone’s paying attention.

No Shared Definition of Success

An agency engagement that starts without an explicit, written, mutually agreed definition of what success looks like by what date is already in trouble, even if nobody notices yet. Vague goals like “grow our presence” or “improve performance” let both sides walk away from the same quarter with completely different impressions of how it went — the agency feels they delivered, the client feels underwhelmed, and neither interpretation is provably wrong, because nothing specific was ever agreed on. The fix is almost embarrassingly simple: a short, specific, numeric goal, agreed before work starts, reviewed on a fixed schedule.

Access Gets Rationed Instead of Granted

Agencies that are kept at arm’s length — limited access to real performance data, limited access to the people who actually make product or pricing decisions, briefed only through a single intermediary who filters information — tend to produce work that’s technically competent but strategically shallow, because they’re working with an incomplete picture by design. The agencies that produce the strongest work are the ones treated closer to an extension of the internal team, with real access to context, not just a vendor executing a narrow brief with limited visibility into why it matters.

Feedback Arrives Too Late to Act On

A quarterly review, as the only structured feedback mechanism, means three months can pass before a misaligned direction gets corrected. By then, a meaningful amount of budget has already gone toward the wrong approach. A lightweight, more frequent check-in — even a brief biweekly review of a few key numbers — catches drift early enough to adjust course before it becomes an expensive problem that only surfaces in a quarterly post-mortem.

Nobody Owns the Relationship Internally

Agency relationships that drift tend to have no single internal owner clearly accountable for the relationship’s success — feedback comes from multiple people with different priorities, none of them fully responsible for the outcome. Assigning one clear internal owner, who synthesizes feedback and makes final calls, mirrors the same discipline that makes internal creative production work well, and it matters just as much when the team producing the work sits outside the building.

None of these fixes require switching agencies. They require the client side doing its part of the relationship with the same discipline it expects from the agency — which, in my experience, is where most of the real leverage actually sits.