Error Recovery Skill

Pattern for handling subagent failures gracefully with appropriate retry strategies.

When to Load This Skill

•You are spawning subagents that may fail
•A subagent returned an error or unexpected output
•You need to decide whether to retry, escalate, or abort

Failure Categories

Category	Symptoms	Strategy
Transient	Timeout, malformed output, parsing error	Simple Retry
Context Gap	"I don't have enough information", unclear task	Context Enhancement
Complexity	Partial completion, scope creep, tangents	Scope Reduction
Boundary/Contract	`status: blocked`, boundary_violation, contract_change	Escalation
Fatal	Repeated failures (3+), fundamental misunderstanding	Abort with Report

Retry Strategies

Strategy 1: Simple Retry

For transient failures. Same prompt, up to 3 attempts.

code

# Track attempts
attempts: 0
max_attempts: 3

# On failure
IF attempts < max_attempts:
  attempts += 1
  Task(same_subagent_type, same_model, same_prompt)
ELSE:
  Mark as FAILED, move on

Use when:

•Output was malformed or truncated
•Timeout occurred
•Agent returned empty/null response

Strategy 2: Context Enhancement

Add more information to help the agent succeed.

code

Task(
  subagent_type: "implementer",
  model: "sonnet",
  prompt: |
    ## PREVIOUS ATTEMPT FAILED

    Error: {error_message}
    Output received: {partial_output}

    ## ADDITIONAL CONTEXT

    Here is more information that may help:
    - Related file: @{additional_file_path}
    - Pattern to follow: {example_pattern}
    - Specific guidance: {clarification}

    ## ORIGINAL TASK

    {original_task_description}

    Output to: {output_path}
)

Use when:

•Agent said "I don't understand" or "unclear requirements"
•Agent made incorrect assumptions
•Agent asked questions in output

Context to add:

•Related code files the agent might need
•Similar implementations as examples
•Explicit clarification of ambiguous points
•Error message from previous attempt

Strategy 3: Scope Reduction

Break the failing task into smaller, more manageable pieces.

code

# Original task failed
Task: "Implement full authentication system"

# Split into subtasks
Task(implementer, "Implement password hashing utility")
Task(implementer, "Implement session token generation")
Task(implementer, "Implement login endpoint")
Task(implementer, "Implement logout endpoint")

Use when:

•Agent completed partial work then failed
•Task description was too broad
•Agent went off on tangents
•Output shows confusion about scope

Splitting guidelines:

•Each subtask should be independently completable
•Each subtask should have clear boundaries
•Subtasks can run in parallel if no dependencies
•Recombine outputs after all subtasks complete

Strategy 4: Escalation

Route to specialized agent for resolution.

code

# For boundary violations
Task(
  subagent_type: "contract-resolver",
  model: "sonnet",
  prompt: |
    A task is blocked due to boundary/contract issues.

    Blocked task output: memory/tasks/{task_id}/output.json
    Blocked reason: {blocked_reason}
    Current contracts: {contract_paths}

    Analyze impact and provide resolution.
    Output to: memory/contracts/resolution_{task_id}.json
)

Escalation paths:

Failure Type	Escalate To	Action
`blocked_reason: boundary_violation`	contract-resolver	Expand boundaries or redesign
`blocked_reason: contract_change`	contract-resolver	Modify contract, re-verify dependents
`blocked_reason: dependency_issue`	executor (self)	Re-check dependency status
Repeated implementation failures	architect	Reconsider design approach

Strategy 5: Abort with Report

When recovery is not possible, fail gracefully.

json

{"tasks":[{"id":"{task_id}","status":"failed","failure_reason":"{specific reason}","attempts_made":3,"recovery_attempted":[{"strategy":"simple_retry","result":"same_error"},{"strategy":"context_enhancement","result":"different_error"},{"strategy":"scope_reduction","result":"subtasks_also_failed"}],"recommendation":"Task may need architectural redesign"}]}

Use when:

•3+ retry attempts failed
•Different strategies all failed
•Fundamental misunderstanding of requirements
•Task is actually impossible given constraints

Decision Tree

code

On Subagent Failure:
│
├─ Is output malformed/empty/timeout?
│  └─ YES → Strategy 1: Simple Retry (up to 3x)
│
├─ Did agent say "unclear" or ask questions?
│  └─ YES → Strategy 2: Context Enhancement
│
├─ Did agent complete partial work?
│  └─ YES → Strategy 3: Scope Reduction
│
├─ Is status "blocked" with boundary/contract reason?
│  └─ YES → Strategy 4: Escalation to contract-resolver
│
├─ Have we tried 3+ strategies already?
│  └─ YES → Strategy 5: Abort with Report
│
└─ Unknown error
   └─ Try Strategy 2 first, then escalate

Retry State Tracking

Track retry attempts in the execution state file:

json

{"tasks":[{"id":"task-001","status":"running","attempts":2,"last_error":"Timeout after 120s","retry_strategy":"simple_retry"},{"id":"task-002","status":"running","attempts":1,"last_error":"Needs access to src/config/db.ts","retry_strategy":"context_enhancement","context_added":["src/config/db.ts","src/types/config.ts"]}]}

Integration with Executor Loop

code

# Enhanced execution loop
WHILE tasks remain incomplete:
  1. Read state file
  2. Find ready tasks
  3. Spawn ready tasks
  4. Check completed tasks:
     FOR each completed task:
       IF status == pre_complete:
         spawn verifier
       ELIF status == blocked:
         apply Strategy 4 (Escalation)
       ELIF status == failed:
         determine_failure_category()
         apply_appropriate_strategy()
         update_retry_state()
  5. Update state file
  6. IF all verified: EXIT
  7. IF all failed with no recovery: EXIT with failure report

Principles

•Fail fast, recover smart - Don't retry blindly; analyze the failure first
•Preserve partial work - If agent completed 50%, don't discard it
•Escalate early - Boundary/contract issues need resolver, not retries
•Track everything - Log all attempts for reflection phase
•Know when to quit - 3 failed strategies = abort, don't loop forever