Audit Log: Fail-Closed JSONL Record of Every Tool Call

Cynative’s JSONL audit log records every tool call with agent provenance, decisions, and redacted results. Configure path, rotation, and retention.

Every tool call Cynative makes is recorded to a persistent JSONL audit log at ~/.cynative/audit.log. The log is on by default and fail-closed: if a call cannot be recorded, the run aborts rather than proceeding without a trail. This gives you a complete, tamper-evident record of every action the model took — what it called, with what arguments, what decision was made, and which agent prompted it.

What gets logged

Every tool call produces one or more JSONL records. Each record captures:

Field	Description
time	UTC timestamp of when the record was written.
seq	Monotonically increasing sequence number within the session.
session_id	Identifies the interactive session.
run_id	Identifies the individual task run within the session.
call_id	Unique identifier for this specific tool call.
parent_call_id	For child records (e.g. reads made by an api_reference lookup), the call ID of the parent. Empty on all other records.
depth	Nesting depth of the call (0 for top-level calls).
actor	The LLM provider and model that made the call (e.g. anthropic/claude-opus-5).
agent	Agent provenance — name, source (builtin or user), and SHA-256 of the exact agent file bytes. Present when an agent framed the run.
phase	attempt (the call is about to run) or result (the call completed).
tool	Name of the tool called (e.g. http_request, code_execution).
arguments	The call’s arguments as a JSON object.
decision	How the call was authorized: approved (operator pressed y), approved_session (operator pressed a), ungated (an orchestration tool that requires no approval), unprompted (a targeted metadata read that runs without a prompt by design), or denied.
outcome	Result of the call: ok, denied, or error.
result	Redacted tool result (see Redaction below).
route	For http_request results, the egress route: direct or proxy. Empty for all other records.

Every record from an agent run also includes the agent’s name, source, and SHA-256 file digest — so any finding can be traced back to the exact prompt revision that produced it.

Redaction

Tool results are redacted before they are written to the log. Cynative’s redactor scans the result string for secret-shaped values (API keys, tokens, credentials) and replaces them before the record is persisted.

Approval-prompt arguments are stored verbatim — they match exactly what you saw and approved at the prompt. Arguments for calls that were never shown at an approval prompt (inner code_execution calls, ungated orchestration tools, and unknown tools) are also redacted before logging, so a resolved secret that a script or the model copied from earlier output is never persisted.

The log can hold sensitive values from approval-prompt arguments — for example, a URL containing a signed token or a parameter derived from secret output. The log file is created with mode 0600 and is readable only by the user who ran Cynative. Treat it with the same care as other credential material on the host.

Fail-closed behavior

The audit log is fail-closed by design. If any of the following occur, the run aborts immediately rather than continuing without a complete record:

• A record cannot be marshaled to JSON.
• A record cannot be written to the log file (e.g. disk full, permissions error).
• The log file cannot be opened at startup.

This means you can rely on the absence of a record to mean a call did not happen — the log is not best-effort. The only exception is retention pruning and compression, which run asynchronously and do not affect the fail-closed write path.

Configuration

Configure the audit log under audit: in ~/.cynative/config.yaml, or via environment variable. Environment variables override the config file.

Config key	Env var	Default	Description
audit.enabled	CYNATIVE_AUDIT_ENABLED	true	Set to false to disable the audit log entirely.
audit.path	CYNATIVE_AUDIT_PATH	~/.cynative/audit.log	Path to the JSONL log file. The parent directory is created automatically if it does not exist.
audit.max_size_mb	CYNATIVE_AUDIT_MAX_SIZE_MB	100	Maximum size in megabytes before the log rotates.
audit.retention_days	CYNATIVE_AUDIT_RETENTION_DAYS	30	Number of days to retain rotated log files.
audit.compress	CYNATIVE_AUDIT_COMPRESS	false	Compress rotated log files with gzip.

Example ~/.cynative/config.yaml snippet:

audit:
  enabled: true
  path: ~/.cynative/audit.log
  max_size_mb: 100
  retention_days: 30
  compress: false

Rotation and retention are handled by a size-rotating, age-retaining writer. When the active log file reaches max_size_mb, it is renamed and a new file is opened. Files older than retention_days are pruned on the next rotation. If compress is true, rotated files are gzip-compressed asynchronously.