Where Postcept fits, and where it doesn't
Authorization checks whether an agent may act. Observability shows what happened in the trace. Postcept verifies whether the action actually completed correctly in the system of record. These categories are complementary, Postcept adds Proof-of-Completion on top of your existing stack.
Why the trace isn’t enough
Independent research, “From Confident Closing to Silent Failure” (arXiv:2606.09863), found that LLM-judge monitors detect false success at no better than 0.65 AUROC, and only 0.54 on API-call traces: near chance. The judges anchor on the agent’s confident closing language as evidence of completion, and a false success produces exactly that language. Whether the action actually happened is a different question, and trace-only monitoring cannot establish the final business state unless that state is independently observed.
| Category | What it answers | Where Postcept is different |
|---|---|---|
| Authorization | Can the agent act? | Postcept verifies whether the action completed correctly. |
| Observability | What happened in the trace? | Postcept checks the source of truth. |
| Evals | Did behavior look successful? | Postcept verifies business state. |
| Workflow engines | How should retries and execution run? | Postcept proves external completion. |
| Reconciliation | What mismatched later? | Postcept verifies at the agent-action level. |
| Postcept | Did the action reach the required final state? | Deterministic outcome verification against the system of record. |
The post-execution camp
Three camps surround agent reliability. Authorization gates actions before they run. Observability and evals inspect the trace during and after. A newer post-execution camp checks the system of record after the agent acts, which is the same question Postcept asks.
Postcept’s distinction inside that camp is the shape of the proof. Verification is independent of the agent, runs continuously, re-checked over time, not once, and rolls up into a single number, your Verified Completion Rate. Each check emits an independently verifiable signed receipt, recorded in a public transparency log: evidence you can hand a risk team, not just a dashboard you watch.
When code you write yourself is enough
A competent backend team can verify one synchronous provider action with idempotency keys, webhooks, a direct re-read, and a reconciliation worker. For a single Stripe refund path with mature reconciliation already in place, that can be enough, and we will say so.
Postcept earns its place when the checking has to be maintained rather than written once: provider state vocabularies that drift, one business promise spanning payment and support systems, pending and reversed and indeterminate outcomes handled explicitly, duplicates correlated on the operation rather than guessed, evidence that travels outside your infrastructure, and re-verification that keeps running after the sprint ends. That is the code nobody wants to own for fifteen providers, and it is the whole product here.
When not to use Postcept
A low-cost, instantly reversible action with no customer-facing completion claim does not need a completion gate. Neither does a workflow where a human already confirms the outcome in the system of record before anyone is told it is done. Start with the actions where a wrong “done” costs money or trust: refunds, credits, cancellations, and the tickets that close on top of them.
What Postcept is not
Postcept is not a generic AI governance platform, an observability tool, a trace viewer, an LLM judge, an agent authorization layer, a workflow engine, a fintech reconciliation tool, or an agent security scanner. It is one focused primitive: deterministic, action-level verification against the system of record.
The trace is not the truth. The system of record is.
Add outcome verification to your stack.
Keep your agent framework, workflow engine, and approvals. Postcept verifies completion on top.