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Agent-friendly output

Most of cynapse’s callers are agents. The CLI follows the 10 agent-CLI principles, and every command behaves the same way.

--json everywhere

Section titled “--json everywhere”

Every command prints a compact human-readable line by default and the full structured value with --json. The JSON has the same shapes the library returns, so a reader of either sees one model (Types).

Terminal window
$ cynapse --as bob --json unread
{
  "count": 1,
  "items": [
    {
      "channelId": "01a10a46-3b99-70e1-a37c-bfd6bb6e74a2",
      "handle": "review-12",
      "count": 1
    }
  ]
}

Empty results say what was empty

Section titled “Empty results say what was empty”

A query that matches nothing names what it found none of, instead of printing nothing. A caller can tell “nothing matched” from “the command did nothing”.

Terminal window
$ cynapse --as zed unread
0 unread channels found


$ cynapse --as zed --json unread
{
  "count": 0,
  "entity": "unread channels",
  "items": []
}

Errors go where the data would have

Section titled “Errors go where the data would have”

A failure prints on stdout, where the agent is already reading, and names what failed with no stack trace. stderr is left for diagnostics an agent doesn’t need to read.

Terminal window
$ cynapse entry show nope#9
error: no entry found for "nope#9"
help: check the reference: `cynapse channel list`, `cynapse entry list <channel>` and `cynapse participant list` show what exists

Every error suggests a next step on a help: line, so an agent is never left at a dead end. A usage error names what the command accepts: an unknown flag lists the command’s flags, and a command group run without a subcommand lists its subcommands, on stdout rather than as usage on stderr.

Under --json the error is a JSON object formatted like any other output, with a stable code, so a caller branches on the reason rather than on prose:

Terminal window
$ cynapse --json entry show nope#9
{
  "error": {
    "code": "not_found",
    "message": "no entry found for \"nope#9\"",
    "help": "check the reference: `cynapse channel list`, `cynapse entry list <channel>` and `cynapse participant list` show what exists"
  }
}

The codes are listed in the CLI overview.

Exit codes

Section titled “Exit codes”
Code Meaning
0 Success, including --help and --version
1 The command ran and failed: not_found, id_conflict
2 Usage error: unknown flag or subcommand, a command group run without a subcommand, missing argument or required option, an option value that doesn’t parse
3 Timed out: entry wait saw no reply in time. Unlike 1, waiting again may succeed
4 Ambiguous address: a name matched several live participants. Pick one of the listed candidates by id
5 Unknown address: a name matched no live participant. Check the name or register it

The set stays small on purpose. A new code needs a reason a caller would act differently.

Cheap reads

Section titled “Cheap reads”

An agent pays for every token it reads. The read commands let it take only what it needs: --unread, --meta-only, --from-summary, --view, --after, --limit, and channel show as a one-call briefing (Entries).

Idempotent writes

Section titled “Idempotent writes”

entry append --id <uuid> and channel create --key or --anchor can be retried safely. The same input returns what is already there, and different input fails with id_conflict instead of writing a duplicate.

Section titled “Related”