* Plan: flesh out PR7 (MCP server + Agent Skill) design
stdio transport (no HTTP port), mlr mcp terminal in the main binary,
SDK-vs-handroll decision, tool list, in-process vs subprocess split,
run-tool safety (--no-shell prerequisite), single-sourced skill, tests.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Add mlr mcp: MCP server + agent playbook; --no-shell gate (#2098 PR7)
New terminal `mlr mcp` runs a Model Context Protocol server over stdio
(spawned by MCP clients; no network port), exposing five tools --
list_capabilities, which, validate_dsl, describe_data, run -- plus an
agent playbook as MCP prompt/resource. Catalog tools are served
in-process from the help registries; the rest subprocess this same
binary with MLR_ERRORS_JSON=1, a timeout, and an output cap.
Prerequisite: a new --no-shell flag / MLR_NO_SHELL env var (one-way
gate) disables the DSL system/exec functions, piped redirects, and
--prepipe/--prepipex; the MCP server sets it on the commands it runs
unless started with --allow-shell.
Adds the github.com/modelcontextprotocol/go-sdk dependency.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Force LF checkout for the embedded SKILL.md (Windows CI fix)
go:embed embeds checkout bytes, so a CRLF checkout on Windows made the
embedded playbook differ per platform and failed
TestPlaybookHasFrontmatter. Pin the file to eol=lf in .gitattributes.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Move no-shell test DSL into per-case mlr files (Windows CI fix)
Inline single-quoted DSL in cmd files is mangled by the Windows shell
(single quotes are not quote characters there); the harness's
put -f ${CASEDIR}/mlr pattern avoids shell quoting entirely.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
One output record per input field: types seen with counts, occurrence
count, null count, cardinality, min/max, and -- for fields within the
-n/--max-values cap -- the complete distinct-value list in first-seen
order. `mlr --ojson describe` is the machine-readable form; nested
types/values flatten in tabular formats.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Lets an agent type-check a DSL expression before spending a full input
pass. `mlr put --explain '...'` (and filter) runs the existing
parse -> ValidateAST -> CST build -> Resolve path, then:
- valid: prints "mlr {put,filter}: DSL expression is valid." and exits 0
- invalid: returns the build error up the normal path, so --errors-json
emits a structured document; exits 1
- -W with fatal warnings: reports and exits 1
The gate lives in the pass-two constructor, before any input file is
opened, so no input stream is read (verified with a nonexistent input
file still validating OK).
Also categorize bare "parse error: ..." messages from the DSL parser as
kind "dsl-parse-error" rather than "generic" (climain/errors_json.go),
so --explain --errors-json gives an agent a useful error kind. The CSV
reader's "parse error on line ..." is stream-time and never reaches this
command-line-parse categorizer.
Tests: dsl-explain/0001-0004 regression cases (valid put/filter, invalid
plain, invalid --errors-json) and categorize unit tests. Regenerated
verb docs, manpage, and the help usage-verbs golden case.
The older -X ("exit after parsing") still exits 0 even on a parse error;
left as-is since --explain is the correct validation path.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
* Tier-2 structured verb options: OptionSpec, initial migration (#2098)
PR 3 of the AI-friendly roadmap (plans/plan-2098-llm.md).
Infrastructure:
- Add OptionSpec{Flag,Arg,Type,Desc,Repeatable,Values} to
pkg/transformers/aaa_record_transformer.go alongside TransformerSetup.
Type is one of: bool, string, int, float, csv-list, regex, filename,
format, enum. For type=="enum", Values lists the valid choices.
- Add Options []OptionSpec to TransformerSetup (nil = not yet migrated).
- Emit Options in VerbInfoForJSON (omitempty so unmigrated verbs stay
backward-compatible; agents check key presence for Tier-2 availability).
UsageText is always present as the Tier-1 prose fallback.
- Add VerbOptionsNilCheck() in aaa_verb_options_check.go: progress report
of migrated vs. unmigrated verbs, analogous to FLAG_TABLE.NilCheck().
- Wire verb-options-nil-check into mlr help (internal/docgen section).
Initial migration (5/70 verbs):
- nothing: empty Options (no verb-specific options, explicitly migrated)
- cat: -n (bool), -N (string), -g (csv-list), --filename, --filenum (bool)
- head: -g (csv-list), -n (int)
- tail: -g (csv-list), -n (int)
- tee: -a, -p (bool)
Tests:
- 5 new unit tests in aaa_transformer_json_test.go covering migrated/
unmigrated paths, field population, JSON round-trip, and key-presence.
- Regression test case 0003: mlr help verb-options-nil-check golden output.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* Migrate all 70 verbs to structured OptionSpec; bump catalog schema to v2
Completes the Tier-2 migration started in the previous commit. Every verb
in TRANSFORMER_LOOKUP_TABLE now has a non-nil Options field.
- Workflow-migrated all 65 remaining verbs. Each Setup var now carries
Options: []OptionSpec{...} with Flag/Arg/Type/Desc fields. Verbs with
no verb-specific options (altkv, check, group-like, nothing, etc.) use
an empty slice to signal "migrated but no options."
- Drop `omitempty` from VerbInfoForJSON.Options: empty slices were silently
dropped, making migrated-no-option verbs indistinguishable from unmigrated
ones in JSON. Without omitempty: null=unmigrated, []=migrated-no-options,
[...]= migrated-with-options. Bump catalogSchemaVersion 1→2 for this shape
change.
- Replace the two "unmigrated-verb" unit tests (which used stats1 as an
example) with TestAllVerbsFullyMigrated (asserts every verb has non-nil
Options) and TestAllVerbsHaveOptionsKeyInJSON (asserts every migrated
verb emits the "options" key in JSON).
- Regenerate test/cases/cli-help/0003/expout: now reads
"Verb options migration: 70/70 migrated."
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* remove a transitional helper
* git rms
* Render verb usage Options blocks from structured OptionSpec
Each verb's usage message and its Tier-2 OptionSpec list previously
duplicated the option text. New WriteVerbOptions (aaa_verb_usage.go)
renders the "Options:" block from the specs: aligned flag column,
descriptions word-wrapped at 80, uniform trailing -h|--help line.
- OptionSpec gains Aliases (JSON "aliases") so long-form spellings
like join's --lk|--left-keep-field-names survive in both outputs
- All 70 verbs migrated; options literals hoisted to package-level
vars (usage funcs can't reference their Setup var without a Go
init cycle)
- Hand-written per-option details the specs had condensed away are
merged into Desc, enriching the JSON catalog
- Non-option prose (examples, cross-references, dynamic accumulator
listings) kept verbatim
- Regenerated the six usage-embedding regression expectations and
the two affected doc pages
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Fix pre-existing usage-text bugs surfaced by the OptionSpec migration
- gap: usage said "One of -f or -g is required" but the parser takes
-n or -g
- seqgen: drop description line copy-pasted from cat ("Passes input
records directly to output...") which contradicted "Discards the
input record stream"
- utf8-to-latin1: description read inverted ("from Latin-1 to UTF-8")
- sec2gmtdate: usage said "../c/mlr" instead of "mlr"
- top: document the accepted-but-undocumented --max flag
- stats2: add linreg-pca to the -a enum values, matching the runtime
accumulator table
Regression expectations and docs regenerated accordingly.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Fix check usage sentence order; stats1 usage blank line to usage stream
- check: the description's second and third lines were swapped,
reading "Consumes records without printing any output, / Useful for
doing a well-formatted check on input data. / with the exception
that warnings are printed to stderr."
- stats1: a bare fmt.Println() in the usage func wrote its blank line
to process stdout instead of the usage output stream
Regression expectation and docs regenerated.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* Add roadmap doc for making Miller AI-friendly (#2098)
Living roadmap derived from issue #2098 and @aborruso's comment:
PR-by-PR arc from a machine-readable help catalog (mlr help --as-json)
through structured verb options, structured errors, DSL validate,
mlr describe, and an MCP server + agent skill.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Clarify PR3 enums are static codelists, not data-dependent constraints
Distinguish @aborruso's codelist (binary-fixed values, PR3) from
constraint (input-dependent values, PR6 mlr describe).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
