Plandex

Plandex is an open-source terminal AI coding engine for complex tasks on large codebases.

Configuration example. Menu and setting names can differ slightly between Plandex versions.

Shared env vars live on Connect a Coding Agent #setup.

Setup#

Plandex accepts an OpenAI-compatible address as a custom provider only on a server you host yourself.

Create a key that starts with plm_ in the API keys menu, then run export PLEUM_API_KEY=plm_xxxxxxxxxxxxxxxx in your terminal. Replace plm_xxxxxxxxxxxxxxxx with the key you copied.
Open the custom models file with plandex models custom and add the entry below to the providers array.
In the model definition's providers, set provider to custom, customProvider to pleum, and modelName to an ID from the model catalog. Follow the custom models page of the official Plandex docs for the rest of the format.

custom models file

{
  "providers": [
    {
      "name": "pleum",
      "baseUrl": "https://apirouter.pleum.ai/v1",
      "apiKeyEnvVar": "PLEUM_API_KEY"
    }
  ]
}

Verify#

Send a short prompt. If a reply arrives, the connection works. Look up cost with the X-Request-Id response header at GET /v1/generation?id=….

How it works#

This tool sends OpenAI Chat Completions requests (/v1/chat/completions). The base URL is https://apirouter.pleum.ai/v1 and auth sends your plm_ key as Authorization: Bearer.

Errors#

plm_xxxxxxxxxxxxxxxx in snippets is a dummy. Replace it with a real key from the dashboard's API Keys page. Do not append /chat/completions to the base URL.

Symptom	Cause and fix
401 Unauthorized	The key is wrong or disabled. Copy the `plm_` key again from the dashboard's API keys page, and make sure it is not another service's key.
402 Payment Required	You are out of credits, or the key used up its daily, weekly or monthly budget or its monthly token limit. Top up, or check the budget and limits on your API key.
404 Not Found	The base URL is wrong, or the model ID is not in the catalog. OpenAI-compatible tools end at `/v1`; Anthropic and Gemini tools take the bare origin without `/v1`. Do not append paths like `/chat/completions` yourself. If the error code is `model_not_found`, check the model ID.
429 Too Many Requests	The key exceeded its per-minute request limit or the concurrent-request limit (`concurrency_limit_exceeded`), or the model provider's own limit was hit (`upstream_rate_limited`). Reduce the agent's parallel runs and check Usage limits.
model not found	That model ID is not in the catalog. Check the exact ID with `GET /v1/models`, including case.

Cost & security tips#

Set a budget on the key. A coding agent calls the model many times per task and resends long context. Daily, weekly or monthly budgets on your API key make costs easier to predict.
Keep the key out of git. Make sure a key in your shell profile or config file never gets committed, and if you suspect a leak, revoke it in the dashboard and issue a new one.
Check where sensitive code goes. Prompts and code are sent to the provider of the model you pick. Use Data residency and PII masking to control that.