feat(acp): accept extra MCP servers via BUZZ_ACP_EXTRA_MCP_COMMANDS - #6651
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BradGroux wants to merge 3 commits into
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feat(acp): accept extra MCP servers via BUZZ_ACP_EXTRA_MCP_COMMANDS#6651BradGroux wants to merge 3 commits into
BradGroux wants to merge 3 commits into
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Desktop-managed Buzz agents could only use one MCP server (buzz-dev-mcp). Users who wanted web search or other third-party MCP tools alongside the built-in local tools had no way to add them — the desktop flow hardcodes a single MCP command and build_mcp_servers() always returned a vec of one entry. Added BUZZ_ACP_EXTRA_MCP_COMMANDS, a comma-separated env var where each entry is split on whitespace into command + args. build_mcp_servers() appends each as a separate McpServer after the primary server. Extra servers do not receive Buzz relay credentials (BUZZ_RELAY_URL, BUZZ_PRIVATE_KEY) or auth tags — they are third-party tools, not Buzz-native MCP servers. The primary mcp_command short-circuit is preserved: if it is empty, no servers are returned at all, even when extra commands are configured. This is option 1 from issue block#6023. It unblocks the web-search use case (e.g. npx -y mcp-remote https://mcp.tavily.com/mcp/...) without desktop UI changes. Closes block#6023 Signed-off-by: dm-builder <f01486f036641ccb52c11bb1e0ff2346ea89a8b4e3b49cd772249948f6fcbae6@digitalmeld.communities.buzz.xyz> Co-authored-by: Brad Groux <bradgroux@users.noreply.github.com> Signed-off-by: Brad Groux <bradgroux@users.noreply.github.com>
Two correctness issues in the extra MCP server path: 1. Server names derived only from the executable stem collided for common multi-server configurations. Two wrappers like 'npx -y first-mcp' and 'npx -y second-mcp' both became 'npx', tripping McpRegistry's duplicate check at spawn. Now disambiguate with a numeric suffix (npx, npx-2). 2. split_whitespace() corrupted quoted executable paths and arguments containing spaces. Replace with shlex::split, which handles standard shell quoting. Malformed entries are skipped with a warning instead of being silently reinterpreted. Also update the config doc comment to document the delimiter/quoting contract. Addresses themiguelamador's review feedback. Co-authored-by: Brad Groux <brad@digitalmeld.com> Signed-off-by: Brad Groux <brad@digitalmeld.com>
…e sanitization Four issues from wesbillman/Carl's review: P0 — Extra MCP processes received Buzz identity credentials despite the PR's isolation claim. build_mcp_servers gave extras an empty per-server env, but buzz-agent's spawn_one cleared and repopulated every MCP child's environment from PASSTHROUGH_ENV, which includes BUZZ_PRIVATE_KEY, BUZZ_RELAY_URL, and BUZZ_AUTH_TAG. Added a trusted flag to McpServer and McpServerStdio; spawn_one now withholds identity credentials from untrusted servers. The primary buzz-dev-mcp server is trusted; extras are not. P1 — BUZZ_ACP_EXTRA_MCP_COMMANDS was absent from Desktop's reserved env key list, allowing a portable persona or per-agent env to inject an arbitrary command. Added to reserved_env_keys.rs and its test. P1 — Malformed quoting logged the raw command (which may contain an embedded API key) and silently skipped the entry. Now fails closed with only the entry index; the raw command is never echoed. P1 — Generated names used the executable stem verbatim, violating McpRegistry's ASCII alphanumeric/hyphen and 128-byte contract. Added sanitize_mcp_name to replace non-conforming characters with hyphens, strip leading/trailing hyphens, and truncate to 128 bytes. Co-authored-by: Brad Groux <brad@digitalmeld.com> Signed-off-by: Brad Groux <brad@digitalmeld.com>
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What users saw
Desktop-managed Buzz agents could receive only the built-in
buzz-dev-mcpserver. Operators had no process-level way to attach additional MCP servers to the ACP session.What changed
BUZZ_ACP_EXTRA_MCP_COMMANDSfor comma-separated extra MCP server commands..env.example.Example:
BUZZ_ACP_EXTRA_MCP_COMMANDS='npx -y first-mcp,"/opt/MCP Servers/second" --stdio'Verification
just cicargo test -p buzz-acp --quiet(786 unit tests and 9 lifecycle tests)cargo clippy -p buzz-acp --all-targets -- -D warningsNon-goals
Closes #6023