CLI Exit Codes and HTTP Status Mapping

agent-bom exposes the same domain through a CLI, an HTTP API, an MCP server, and a GitHub Action. CI gates and shell pipelines branch on agent-bom's exit code; HTTP clients branch on the API's status code. This page is the single contract that documents both, so a script writer never has to read the source to know what an exit code means.

CLI exit-code contract

The contract covers ok, findings, usage, auth, and server failures explicitly so automation can distinguish caller mistakes from control-plane outages.

Code	Name	Meaning	Typical sources
0	success	Command completed; no findings or all findings under the configured severity threshold.	Any subcommand that finished cleanly.
1	operational failure	A precondition failed: missing config, unreachable backend, missing required env var, dependency not present.	--clickhouse-url missing, NVD unreachable, optional dependency not installed.
2	usage or empty	Invalid arguments, no input to act on, or report contained no rows after filtering.	Click UsageError (auto), agent-bom skills audit with no skill files, empty result rendering.
3	(reserved)	Reserved for "policy gate failed" — declared so future policy commands have a stable code to use.	Not yet emitted.
4	(reserved)	Reserved for "auth required" / "auth invalid" on commands that talk to an authenticated control plane.	Not yet emitted.
5	(reserved)	Reserved for "remote control-plane error" (5xx response from the API).	Not yet emitted.
130	interrupted	Process received SIGINT (Ctrl-C) — POSIX convention, kept for shell idiom compatibility.	Long-running agent-bom proxy / agent-bom serve / agent-bom agents.
*	subprocess passthrough	When agent-bom shells out (e.g. native scanner binaries), the child's non-zero exit code is propagated.	agent-bom shield, agent-bom run proxy invocations.

The unreserved codes (0, 1, 2, 130) are stable today. Codes 3, 4, 5 are reserved so future product growth has a clean place to land without re-numbering existing codes — operators may rely on if [ "$rc" -eq 0 ] and on the rc != 0 family without further branching today.

API status-code contract

Status	Meaning	Where it's raised
200	Success.	All successful reads and writes.
201	Created.	POST /v1/scan, POST /v1/auth/keys, SCIM POST /Users//Groups.
204	Deleted.	DELETEs that succeed without a body.
400	Bad request — payload validation passed Pydantic but failed business-rule validation.	Tenant-quota update with negative caps, invalid filter combinations.
401	Unauthenticated — no valid API key, OIDC bearer, SAML session, or trusted-proxy attestation.	Middleware before route resolution.
403	Authenticated but not authorized — RBAC scope rule rejected the call.	Cross-tenant access attempt, viewer role attempting admin operation.
404	Resource not found.	Scan job, agent, registry server, key, or graph node not present in tenant.
409	Conflict — idempotency clash, duplicate key creation, concurrent state mutation.	API key rotation, scan-job lifecycle conflicts.
422	Pydantic validation failure — payload shape rejected.	FastAPI request-body validation.
429	Rate limited — per-tenant quota or global rate limit hit.	Middleware PostgresRateLimitStore.
500	Server error — unexpected exception inside route logic.	Bugs, downstream timeouts that escape retry budgets.
502	Upstream bad-gateway — proxied call (e.g. external scanner) returned an unparseable response.	External scanner adapters.
503	Backend unavailable — Postgres, ClickHouse, or another required dependency is down.	Health probes, dependency-aware routes.

All errors return {"detail": "<message>"} per FastAPI default. The UI client at ui/lib/api.ts parses detail, message, and error so that any of those keys surface to operators with a useful string.

How CLI codes correspond to API statuses

This is the explicit mapping that the CLI applies when it talks to the API and needs to translate an HTTP outcome into a process exit code. It's not a reflexive 1:1 mapping — several HTTP codes collapse into a single CLI code because shells care about families, not individual semantics.

CLI exit code	HTTP status family	Why
0	2xx	The command did what it asked.
2	400 422	Caller sent something invalid — usage error, fix the input.
4 (reserved)	401 403	Caller is not (or not yet) authorized — fix credentials, not the input.
1	404 409	Operational state issue — resource missing, conflict — retryable after correcting state.
1	429	Throttled — retry with backoff. Today flattens to 1; future revisions may use a dedicated code.
5 (reserved)	5xx	Control-plane fault — agent-bom is not at fault, retry or escalate.
130	n/a	Operator pressed Ctrl-C; never originates from an HTTP response.

Until reserved codes (3/4/5) are emitted, the safe shell idiom is:

agent-bom agents -p ./project --format sarif > out.sarif
rc=$?
case "$rc" in
  0)   echo "ok" ;;
  2)   echo "usage / empty"; exit 0 ;;     # treat empty as non-failure in some pipelines
  130) echo "interrupted"; exit 130 ;;     # propagate Ctrl-C semantics
  *)   echo "failed (rc=$rc)"; exit "$rc" ;;
esac

GitHub Action action.yml outputs

The composite action surfaces the CLI exit code, parsed scan status, artifact paths, and AI-specific posture counts so downstream workflow steps can gate without re-parsing logs.

Output	Type	Source	Notes
sarif-file	string	computed	Path to the SARIF report when format: sarif was selected.
exit-code	string	propagated CLI exit code	Same value documented in CLI exit-code contract.
scan-status	string	parsed from exit code + findings	clean, violations, or error.
vulnerability-count	string	parsed from SARIF or skills JSON	Number of vulnerability findings, or skill findings for scan-type: skills.
badge-file	string	computed	Path to generated shields.io badge JSON when badge is set.
graph-export-path	string	computed	Path to generated mermaid, svg, graph, or graph-html artifact.
exposure-paths-count	string	parsed from graph-capable JSON	Number of exposure, lateral, or attack paths in the result artifact.
blast-radius-critical-count	string	parsed from SARIF/JSON	Number of critical blast-radius or SARIF findings.
posture-grade	string	derived from parsed counts	Coarse grade: A, C, D, F, or unknown.

Stability guarantees

• 0, 1, 2, 130, and the subprocess passthrough are stable and will not be re-numbered within a major version.
• 3, 4, 5 are reserved and will be assigned only to the meanings declared above.
• The HTTP status mapping is a binding contract for shell pipelines; future status codes added to the API will fold into the same families described above unless a new CLI code is introduced (in which case it will be drawn from the reserved set, not allocated above 5).