Skip to content

audit log stores full response values in cleartext, including secret payloads #71

Description

@rodaddy

Found during the MCP cutover program (development#104, mcpcall prototype lane
dev#107, 2026-08-09).

~/.cache/mcp2cli/logs/audit.ndjson records responseSummary with the full
response body of tool calls. Observed live: a vaultwarden-secrets get_credential entry carrying a complete service-account private key in
cleartext, in an unencrypted cache file, on every box running mcp2cli. Any
credential-returning service has its payloads persisted the same way.

Fix at the mechanism: the audit line should record param KEY NAMES and a
response byte count / status only — never param values, never response bodies.
(The mcpcall prototype's contract adopts exactly that shape;
development:mcp-cutover/prototypes/mcpcall/contract.md §audit.)

Independent of whether mcpcall ships — this is worth fixing in mcp2cli while
it remains the stdio bridge. Also observed in the same log: get_credential
latency of 9691 ms, worth a look while in the file.

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions