RESEARCH • POST‑INCIDENT • CITABLE

CICS Without RESP/RESP2: Hidden Error Paths in Mainframe Applications

Authority posture: This research is cited inside authority records. It is not advice. It explains why authority terminates.

Post‑incident framing: this page defines a provability boundary that can terminate authority in regulated decisions. It is written to be cited inside authority records and to survive scrutiny.

Scope

This page explains what the boundary is, why deterministic guarantees collapse, and how authority records must describe termination without predicting outcomes for other systems.

What RESP and RESP2 mean

In CICS, RESP and RESP2 provide explicit response codes that allow a program to handle error conditions deterministically at the source level.

Without RESP/RESP2, error behavior may be redirected by CICS default handling, HANDLE CONDITION clauses, abend behavior, or region configuration. Those behaviors are runtime-dependent.

Post-incident scrutiny concerns not only the happy path, but whether the system can prove which error paths are possible and how they are handled.

In practice, estates often combine multiple boundary classes. This page isolates one class so that authority language remains precise and citable.

Legacy Lens publishes precedent and invites comparison. It does not predict what will occur in other systems. The boundary definition is provided as a standard reference.

If an authority record cites this page, it should do so to define the evidentiary limit encountered in the analyzed corpus under the declared context.

Why missing RESP collapses provability

Static analysis can identify that a CICS command is invoked. It cannot, from COBOL artifacts alone, prove the region state, file definitions, resource availability, or configuration that controls error conditions.

If RESP/RESP2 is absent, the source does not specify the error path explicitly. Control transfer can occur through runtime mechanisms invisible to the artifact set.

Therefore, deterministic authority cannot assert complete behavior equivalence across replatforming unless the runtime semantics are proven from artifacts — which they typically are not.

In practice, estates often combine multiple boundary classes. This page isolates one class so that authority language remains precise and citable.

Legacy Lens publishes precedent and invites comparison. It does not predict what will occur in other systems. The boundary definition is provided as a standard reference.

If an authority record cites this page, it should do so to define the evidentiary limit encountered in the analyzed corpus under the declared context.

Why config exports do not automatically lift boundaries

CICS configuration exports (CSD/PCT/PPT/FCT) are useful inventory artifacts. They are often delivered as text, CSV, or XML and may not encode full runtime semantics in a form that produces deterministic guarantees.

Even where configuration is present, behavior can still depend on region state (transaction routing, security, timing, resource contention). A static authority standard cannot treat configuration as proof of runtime behavior unless the registry explicitly defines sufficiency rules.

Legacy Lens ingests and hashes these artifacts for completeness, but does not infer runtime semantics from them unless an explicit, audited boundary lifting rule exists.

In practice, estates often combine multiple boundary classes. This page isolates one class so that authority language remains precise and citable.

Legacy Lens publishes precedent and invites comparison. It does not predict what will occur in other systems. The boundary definition is provided as a standard reference.

If an authority record cites this page, it should do so to define the evidentiary limit encountered in the analyzed corpus under the declared context.

Authority record language

Authority records should state: CICS error paths are environment-dependent when RESP/RESP2 is missing; deterministic guarantees terminate.

They should list the call sites and the specific commands involved. They should avoid prescriptive remediation language.

They should cite this page to explain refusal posture under post-incident scrutiny.

In practice, estates often combine multiple boundary classes. This page isolates one class so that authority language remains precise and citable.

Legacy Lens publishes precedent and invites comparison. It does not predict what will occur in other systems. The boundary definition is provided as a standard reference.

If an authority record cites this page, it should do so to define the evidentiary limit encountered in the analyzed corpus under the declared context.

How to cite this research in an authority record

Use language such as:

This decision references Legacy Lens research (RESEARCH_CICS_NO_RESP). The analysis explains a provability boundary where deterministic guarantees collapse. Where provability terminates, authority terminates under the declared governance context.

Explicit non‑claims