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[!FROZEN] MPLP Protocol v1.0.0 Frozen Specification Freeze Date: 2025-12-03 Status: FROZEN (no breaking changes permitted) Governance: MPLP Protocol Governance Committee (MPGC) License: Apache-2.0 Note: Any normative change requires a new protocol version.

Error Handling

[!NOTE] Duty Type: OS-Level Kernel Duty
SOT Reference: README v1.0.0 Section 8

Intent​

To ensure that the system can detect, report, and recover from failures in a deterministic and auditable way, preventing silent failures and zombie states.

Lifecycle Coverage​

  • All Stages: From schema validation errors in Planning to runtime exceptions in Execution.

Agent Scope (SA / MAP)​

  • SA: Retrying failed tool calls, self-correction.
  • MAP: Escalating failures to a supervisor agent.

Required Events​

  • ErrorEmitted
  • RecoveryAttempted
  • CircuitBreakerTripped

Compliance Requirements​

  1. Runtime MUST NOT allow silent failures; all errors must be logged to the Trace.
  2. Runtime MUST support defined recovery strategies (Retry, Ignore, Abort, Escalate).
  3. Errors MUST be structured with standard codes and contexts.

Implementation Details (Non-Normative)​

Error Handling is deeply integrated into the Trace and Event systems.

Trace Status​

The Trace object (mplp-trace.schema.json) and its segments have a status field. Setting this to failed signals a breakdown in the execution flow.

  • status: failed: Indicates an unrecoverable error at that level of abstraction.
  • events: The trace includes a list of error events that provide context (stack traces, error codes).

Runtime Execution Events​

The RuntimeExecutionEvent (events/mplp-runtime-execution-event.schema.json) is the primary vehicle for reporting failures:

  • status: failed: Explicitly marks the event as a failure.
  • payload: Contains the error details, allowing the Runtime to decide on a recovery strategy (Retry, Escalate, etc.).

Schema Reference​

SchemaPurposeKey Fields
mplp-trace.schema.jsonExecution statusstatus, events
events/mplp-runtime-execution-event.schema.jsonError reportingstatus: failed, payload

Examples​

  • Tool Failure: An agent tries to read a non-existent file; Runtime catches the error, logs it, and prompts the agent to check the path.
  • Context Limit: LLM context window exceeded; Runtime triggers a "Summarize & Prune" recovery flow.