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The `claude` adapter

Pinned to 2.1.240. Adapter class: harness — the vendor keeps its loop, its sessions, its tools, its authentication and its credential custody; metaharness drives its documented outside surface.

metaharness run claude --hermetic -p "…"
metaharness conformance claude    # 20 vectors, no model / no network / no credential
metaharness doctor claude

What a run does

Spawns claude into a scratch config home.
Installs a blocking PreToolUse hook and answers its calls per call.
Streams the session out as protocol events on stdout; takes steering on stdin.
Retains the raw transcript.
Exits on the hermetic floor's verdict.

Declared capabilities

Tier	Status
`registration`	`delivered`
`call`	`delivered`
`turn`	`unverified`
`kill`	`delivered`

Command	Support
`tool.decide`	honoured
`interrupt`	honoured
`halt`	honoured
`frame.set`, `message.inject`, `steer`, `permission.set`	refused — `UNSUPPORTED_CONTROL`

steer is refused because Claude Code headless has no mid-turn tier. That is a property of the surface, not an omission in the adapter.

Operation rendering

Neutral operation	Vendor tool
`file.read`	`Read`
`file.write`	`Write`
`file.edit`	`Edit`
`dir.list`	`Glob`
`search`	`Grep`
`shell`	`Bash`
`web.read`	`WebFetch`
`skill.load`	`Skill`
`subagent.spawn`	`Task`
`task.todo`	`TodoWrite`
`mcp.call`	(none)

Print it yourself: metaharness capabilities claude --render.

Three things this crate deliberately does not do


It spawns nothing.	`plan_launch` returns the command line, the child environment, the settings document, the hook definition and the copy list as values — because a consumer asserts its own argv rather than trusting it, "because every one of the failures would be silent". The hook program is the same rule applied to the seam's executable.
It reads no clock.	Every event's timestamp is the one the vendor recorded, passed through — or absent.
It drops nothing.	An unmappable record becomes `opaque` with the vendor's `type`, `subtype`, a digest and its 1-based source line. An unrecognised field is ignored in silence; an unrecognised record is preserved.

The live proof

A frame that admitted no shell met a prompt that asked for one.

metaharness denied the call at the hook.
The call did not run.
The vendor's own terminal record listed Bash in permission_denials.

Two defects that only a paid run could find

Both were metaharness's, and neither was reachable without a real session:

The hermetic floor read the wrong field for "was an API key in use".
It treated "this run pinned no documents" as "nobody found out whether the documents moved" — which made --hermetic strict unpassable.

Both are fixed, both are regression-tested, and both are recorded as design amendment a4.

Evidence discipline

Every claim this adapter makes about the binary is either read from the design document's § 2.7 — where each row carries its own method — or labelled unverified at the point of use, with the open question that would close it.

A string in a binary is weaker than a driven call, and this crate says which it has.

What a run does​

Declared capabilities​

Operation rendering​

Three things this crate deliberately does not do​

The live proof​

Two defects that only a paid run could find​

Evidence discipline​