docs: add an environment-variable reference (#2365)

Every variable that changes runtime behavior now lives on one page,
docs/environment-variables.md: which client reads it, its default, and
its effect. It covers three variables that were undocumented
(MCP_LOG_FILE, MCP_INSPECTOR_LOG_DIR, LOG_LEVEL), the secret-store
variables previously only in the Docker guide, and the Node TLS
variables that answer #1936 (a self-signed https://localhost server).

The README docs table, the migration guide, docker.md and the four
client READMEs link to it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TRJ64MnDTg1TpzCTEV9Xva
Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-09-13 23:35:30 -04:00
commit 2c1d3fdba8

View file

@ -77,7 +77,7 @@ If another process holds the lock and will not let go, the save **fails** rather
It is also what covers the lock being unavailable. This store exists for boxes where the usual mechanism isn't there, so a directory that can't hold a lock file — a read-only `$HOME`, a mount owned by another uid — makes the save proceed unlocked with a warning, rather than turning every `set` into a failure on exactly the deployments the store was written for.
Three env vars affect where the file lands. `MCP_INSPECTOR_SECRET_STORE=keyring|file|memory` picks the store outright, bypassing the probe. `MCP_INSPECTOR_SECRET_FILE` names the file. Failing both, the file follows `MCP_STORAGE_DIR` — the same variable that relocates OAuth tokens and `client.json` — so mounting a volume at your configured storage directory is enough to make secrets durable there.
Three env vars affect where the file lands. `MCP_INSPECTOR_SECRET_STORE=keyring|file|memory` picks the store outright, bypassing the probe. `MCP_INSPECTOR_SECRET_FILE` names the file. Failing both, the file follows `MCP_STORAGE_DIR` — the same variable that relocates OAuth tokens and `client.json` — so mounting a volume at your configured storage directory is enough to make secrets durable there. These variables apply outside a container too; every runtime variable is listed in [Environment variables](./environment-variables.md).
**Upgrading from an image before this fix?** Earlier images did not create `/home/node/.mcp-inspector`, so Docker created the volume's mount point as `root` and the non-root `node` user couldn't write to it. An **empty** volume repairs itself on the first run of a current image (Docker applies the image directory's ownership to an empty volume), but one that already has files in it keeps its old `root` ownership and still fails with `EACCES`. Fix it once: