* feat(transform): add file_read transform for UTF-8 file / stdin content (#277)
Introduces a new ApplyTransform case "file_read":
- Input: a string flag value treated as a UTF-8 file path
- Special case: the path "-" reads from stdin
- Output: the file contents as a string
- Errors surface as validation errors (exit 2) — non-UTF-8, missing
file, empty path, and non-string input all reject cleanly
This is a foundational primitive intended to compose with envelope
schema features so a CLI flag like --content-file can carry a path
that ultimately feeds a string-typed MCP parameter with the file's
contents.
## Scope note — MapsTo intentionally NOT included
The original proposal in #277 paired this transform with a new
CLIFlagOverride.MapsTo field that retargets a flag's value to a
different MCP parameter (e.g. --content / --content-file both feed
the upstream `markdown` param). Pre-production end-to-end validation
(see #282) showed that the MCP registry server-side schema does not
currently recognise `mapsTo` and strips it on serialisation. Every
other new envelope field (hidden / required / transform /
mutuallyExclusive / requireOneOf) survives — only mapsTo is dropped.
Shipping MapsTo without server-side support would land dead client
code. The MapsTo field + sourceFlag transform guard were therefore
removed from this PR; they will return in a follow-up PR once #282
(server-side schema acknowledgement of mapsTo) is resolved. The
file_read transform stays here because it composes with multiple
mechanisms beyond MapsTo and is independently testable.
## Tests
Six new cases in internal/compat/transform_test.go cover the
contract: literal file, stdin via "-", missing file, non-UTF-8
input, empty path, non-string input. All pass under both `go test`
and `go test -coverprofile`.
Refs #277, blocked-by #282
* feat(schema): add CLIFlagOverride.MapsTo for sibling-flag routing (#277#282)
Adds the `MapsTo` field on `CLIFlagOverride` and wires the dispatch loop
in `compat.buildOverrideBindings` so a flag's final value (post-transform
or literal) is routed into a different MCP parameter slot than its own
property name. This lets two sibling CLI flags feed a single upstream
parameter — the canonical case being `--content` (literal) + `--content-file`
(transform: file_read) both mapping to `markdown`.
Tool-level `CLIToolOverride.MutuallyExclusive` (cobra MarkFlagsMutuallyExclusive)
is the right partner for guarding "set one, not both" at parse time; no
new exclusion machinery is added.
Closes the client-side gap previously misattributed to a server-side
mapsTo strip in #282. Once a doc envelope with mapsTo lands in pre-prod,
end-to-end `--content-file` becomes shippable, finishing #277 Step 1b.
Test coverage (internal/compat/dynamic_commands_test.go):
- MapsTo without transform: literal --content → params[markdown]
- MapsTo with file_read transform: --content-file path → params[markdown]
- Sibling flags both mapsTo same target, only one set: clean routing
- Sibling flags both set: rejected by tool-level MutuallyExclusive (regression)
Backward-compat: empty MapsTo preserves existing params[propertyName] write
semantics for every existing envelope.
修雨
49c5bea4f3