Six findings, all taken.
- The descriptor reported the *write policy*, not the file. Adding
`MCP_INSPECTOR_SECRET_KEY` to an install that already has a plaintext
file flipped `store.encrypted` immediately, so the banner and footer
claimed "File (encrypted)" while the existing secrets sat readable
until the next `set`. `FileSecretStore.readOnDiskEncryption()` now
reads the envelope (never the payload, so it needs no passphrase) and
the descriptor is built from that. The transitional state gets its own
`pendingEncryption` flag, which changes the advice without softening
the verdict — "set a passphrase" is the wrong thing to tell someone who
already has, so the caveat names the pending write instead.
- The secrets file ignored the configured storage directory. A container
mounting only that directory was judged unmounted, fell back to
`memory`, and lost secrets the user had arranged to keep.
`defaultSecretFilePath()` now follows `MCP_STORAGE_DIR` — the variable
that already relocates OAuth tokens and `client.json` — between the
explicit `MCP_INSPECTOR_SECRET_FILE` and the `~/.mcp-inspector`
default. (The issue comment called it `MCP_INSPECTOR_STORAGE_DIR`; no
such variable exists.)
- `version` was never checked before the plaintext branch, so a
`{ version: 2, encryption: "none" }` file was read and silently
rewritten as version 1, discarding whatever the newer format added —
the same destroy-to-satisfy-an-additive-request case the encrypted
branch already refuses. Checked first now, so the answer no longer
depends on which encryption mode the newer writer chose.
- The doc comment claimed a per-file salt made "a short, memorable value
safe to use". It does not: the salt defeats precomputation, not
guessing, and the scrypt cost is deliberately a few milliseconds
because it runs on every read and write. Both the comment and the
README now say to use a high-entropy value, generated rather than
chosen.
- `usableSecretStorage` validated only `kind`, so a partial
`{ kind: "file" }` was cast through and — because a missing `plaintext`
is falsy — rendered as the quiet, neutral *encrypted* file. That is the
confident half-answer the guard exists to reject, produced by the
absence of information rather than by any claim the backend made.
`reason`, `durable`, and each kind's own required fields are checked.
- The footer's inline `Tooltip` carried four static props; extracted to a
`CaveatTooltip` constant per the `.withProps()` rule.
Tests cover each: the policy/file disagreement in both directions and the
no-file-yet fallback, `MCP_STORAGE_DIR` and its precedence against
`MCP_INSPECTOR_SECRET_FILE`, the version refusal (asserting the bytes
survive it) split from the unrecognized-cipher refusal it used to be
conflated with, `readOnDiskEncryption` including the keyless and
unparseable cases, five new rejected descriptor shapes, and the changed
caveat. Full `npm run ci` green.
Signed-off-by: cliffhall <cliff@futurescale.com>
Closes#1950
Before this, a box with no reachable OS keychain — the published
container (no D-Bus session, #1848), Android/Termux (no platform binary,
#1905), a minimal Linux install without libsecret — could not persist an
OAuth client secret or a stdio `env:` value at all. `KeyringSecretStore`
degraded into a store that silently holds nothing: `get` returned null,
`delete` no-opped, and `set` hard-failed with a 503. That is the correct
failure behavior, but it left the documented, supported way to run the
Inspector with no secret persistence whatsoever.
Adds the two missing implementations and, more importantly, the policy
that picks one and the surfaces that say which was picked.
- `FileSecretStore` — one `0600` JSON document at
`~/.mcp-inspector/secrets.json`, encrypted with AES-256-GCM whenever
`MCP_INSPECTOR_SECRET_KEY` is set (scrypt, per-file random salt). The
whole map is encrypted as a unit rather than value-by-value so the
account names — `${serverId}:${field}` — are hidden too; a per-value
scheme would leave a readable index of which servers you hold a client
secret for. A file that can no longer be decrypted reads as empty
(matching the interface's read tolerance) but *refuses to be written*,
because replacing a file of still-valid secrets to satisfy an additive
request destroys data.
- `secret-store-selection.ts` — the policy.
`MCP_INSPECTOR_SECRET_STORE=keyring|file|memory` wins outright;
otherwise probe the keychain and, if unreachable, fall back loudly. The
fallback is `memory` in a container whose secrets directory is not on a
mount, and `file` otherwise — so mounting the volume the README already
recommends for the catalog flips the same run to durable storage with
no configuration, and an unmounted container gets the honest answer
rather than a file `--rm` will discard. Cached per process so the
banner, `/api/config`, and the store doing the writing cannot disagree.
- Automatic, but never silent. The downgrade prints at startup, rides
`GET /api/config`, and is named in a permanent 32px footer at the
bottom of both dialogs that accept a secret. A startup banner is seen
once by whoever started the process; a toast is seen once; a
dismissible banner is the thing a user dismisses before doing the work
it describes. The plaintext and memory cases render their caveat inline
in a warning tone — a warning you must hover to discover is not one.
- `SecretStoreUnavailableError` is now the base every store's `set`
throws, so the routes translate one condition into a 503 instead of
matching `KeychainUnavailableError` by name.
Docs: the container section of the root README gains a table of which
store you get and how to make secrets survive, plus the
`MCP_INSPECTOR_SECRET_KEY` upgrade/mismatch rules.
Tests: the existing interface contract block is extracted to
`secretStoreContract.ts` and run against all three implementations, so
none can drift on the availability contract. `FileSecretStore` is tested
against a real temp filesystem — mode, cross-instance round-trip, that
the ciphertext does not contain the plaintext, the read-modify-write
race, and every refusal path. Full `npm run ci` passes, per-file gate
included.
Signed-off-by: cliffhall <cliff@futurescale.com>
cliffhall