ACF
acfstandard.io
Developer docs
FR
Reference

Errors

What acf-mcp returns when a call fails: a JSON-RPC error whose message states precisely what is wrong. The server never guesses a value for you.

iNote
All errors arrive with JSON-RPC code -32603. There is no ACF®-specific error code: the message text tells the cases apart, and it is written to be read by an agent as well as by a human.

Invalid parameters

Every tool validates its inputs against its schema before any computation. A value outside an enum, a missing field or an out-of-range length makes the call fail; the message is the list of issues, each with the offending field (path), the received value and the allowed values.

validation-error.jsonjson
{
  "jsonrpc": "2.0",
  "id": 2,
  "error": {
    "code": -32603,
    "message": "[\n  {\n    \"received\": \"N2\",\n    \"code\": \"invalid_enum_value\",\n    \"options\": [\n      \"suggestive\",\n      \"co_decision\",\n      \"supervised_autonomous\",\n      \"autonomous\"\n    ],\n    \"path\": [\n      \"autonomy_level\"\n    ],\n    \"message\": \"Invalid enum value. Expected 'suggestive' | 'co_decision' | 'supervised_autonomous' | 'autonomous', received 'N2'\"\n  }\n]"
  }
}

A frequent case since 2.0.0: the former acf_level (N0 to N3) is rejected; the field is called autonomy_level and takes the 4 delegated autonomy levels. See Autonomy and maturity.

Resource not found

A code or term that is well-formed but absent from the corpus produces an explicit message:

not-found.jsonjson
{
  "jsonrpc": "2.0",
  "id": 4,
  "error": {
    "code": -32603,
    "message": "Fiche ACF-00 not found in any locale chain for en"
  }
}
  • Fiche ACF-XX not found in any locale chain: card absent, for instance the former ACF-00.
  • Glossary entry not found: …: term not in the glossary; go through acf.search.
  • Article … not found. Available articles for …: article not covered; the message lists the covered ones.
  • Invalid scheme: expected acf://, Unknown ACF URI: malformed URI; get it from resources/list or acf.search.
  • Unknown tool: …: unknown tool name; the list of the 13 tools comes from tools/list.

What to do

  • Fix the value the message points to and call the tool again: no call has side effects, it can be replayed safely.
  • When a tool answers with confidence at low, it is not an error: read assumptions and gaps_to_validate, then complete the input.
  • Check the installed version (npx acf-mcp@latest) if an expected card or tool is missing.

See also