singularity-forge/gsd-orchestrator/references/json-result.md

HeadlessJsonResult Reference

When using --output-format json, SF collects events silently and emits a single HeadlessJsonResult JSON object to stdout at process exit. This is the structured result for orchestrator decision-making.

Obtaining the Result

# Capture the JSON result
RESULT=$(sf headless --output-format json next 2>/dev/null)
EXIT=$?

# Parse fields with jq
echo "$RESULT" | jq '.status'
echo "$RESULT" | jq '.cost.total'
echo "$RESULT" | jq '.nextAction'

Important: Progress text goes to stderr. The JSON result goes to stdout. Redirect stderr to /dev/null when parsing stdout.

Field Reference

Top-Level Fields

Field	Type	Description
status	"success" | "error" | "blocked" | "cancelled" | "timeout"	Final session status. Maps directly to exit codes.
exitCode	number	Process exit code: 0 (success), 1 (error/timeout), 10 (blocked), 11 (cancelled).
sessionId	string | undefined	Session identifier. Pass to --resume <id> to continue this session.
duration	number	Session wall-clock duration in milliseconds.
cost	CostObject	Token usage and cost breakdown. See below.
toolCalls	number	Total number of tool calls made during the session.
events	number	Total number of events processed during the session.
milestone	string | undefined	Active milestone ID (e.g. "M001").
phase	string | undefined	Current SF phase at session end (e.g. "executing", "blocked", "complete").
nextAction	string | undefined	Recommended next action from the state machine (e.g. "dispatch", "complete").
artifacts	string[] | undefined	Paths to artifacts created or modified during the session.
commits	string[] | undefined	Git commit SHAs created during the session.

Status → Exit Code Mapping

Status	Exit Code	Constant	Meaning
success	0	EXIT_SUCCESS	Unit or milestone completed successfully
error	1	EXIT_ERROR	Runtime error or LLM failure
timeout	1	EXIT_ERROR	--timeout deadline exceeded
blocked	10	EXIT_BLOCKED	Execution blocked — needs human intervention
cancelled	11	EXIT_CANCELLED	Cancelled by user or orchestrator

Cost Object

Field	Type	Description
cost.total	number	Total cost in USD for the session.
cost.input_tokens	number	Number of input tokens consumed.
cost.output_tokens	number	Number of output tokens generated.
cost.cache_read_tokens	number	Number of tokens served from prompt cache.
cost.cache_write_tokens	number	Number of tokens written to prompt cache.

Parsing Patterns

Decision-Making After Each Step

RESULT=$(sf headless --output-format json next 2>/dev/null)
EXIT=$?

case $EXIT in
  0)
    PHASE=$(echo "$RESULT" | jq -r '.phase')
    NEXT=$(echo "$RESULT" | jq -r '.nextAction')
    echo "Success — phase: $PHASE, next: $NEXT"
    ;;
  1)
    STATUS=$(echo "$RESULT" | jq -r '.status')
    echo "Failed — status: $STATUS"
    ;;
  10)
    echo "Blocked — needs intervention"
    sf headless query | jq '.state'
    ;;
  11)
    echo "Cancelled"
    ;;
esac

Cost Tracking

RESULT=$(sf headless --output-format json next 2>/dev/null)

COST=$(echo "$RESULT" | jq -r '.cost.total')
INPUT=$(echo "$RESULT" | jq -r '.cost.input_tokens')
OUTPUT=$(echo "$RESULT" | jq -r '.cost.output_tokens')

echo "Cost: \$$COST (${INPUT} in / ${OUTPUT} out)"

Session Resumption

# First run — capture session ID
RESULT=$(sf headless --output-format json next 2>/dev/null)
SESSION_ID=$(echo "$RESULT" | jq -r '.sessionId')

# Resume the same session later
sf headless --resume "$SESSION_ID" --output-format json next 2>/dev/null

Artifact Collection

RESULT=$(sf headless --output-format json auto 2>/dev/null)

# List files created/modified
echo "$RESULT" | jq -r '.artifacts[]?'

# List commits made
echo "$RESULT" | jq -r '.commits[]?'

Example Result

{
  "status": "success",
  "exitCode": 0,
  "sessionId": "abc123def456",
  "duration": 45200,
  "cost": {
    "total": 0.42,
    "input_tokens": 15000,
    "output_tokens": 3500,
    "cache_read_tokens": 8000,
    "cache_write_tokens": 2000
  },
  "toolCalls": 12,
  "events": 87,
  "milestone": "M001",
  "phase": "executing",
  "nextAction": "dispatch",
  "artifacts": [
    ".sf/milestones/M001/slices/S01/tasks/T01-SUMMARY.md"
  ],
  "commits": [
    "a1b2c3d"
  ]
}

Combined with query for Full Picture

The HeadlessJsonResult captures what happened during a session. Use query for the current project state:

# What happened in this step?
RESULT=$(sf headless --output-format json next 2>/dev/null)
echo "$RESULT" | jq '{status, cost: .cost.total, phase}'

# What's the overall project state now?
sf headless query | jq '{phase: .state.phase, progress: .state.progress, totalCost: .cost.total}'