Profile compatibility (canonical)¶

This document is the product-level policy for Assay evidence profiles. Profile specs (privileged-mcp-action/v0, privileged-mcp-action/v1, and successors) link here rather than restating a second compatibility rule.

Selected interpreter versus input identity¶

assay evidence verify-privileged-mcp-action selects an interpreter with --profile-version (default v0 when omitted). The report member profile is that selected interpreter. It is never detected from bundle bytes and is never carried input identity.

Frozen privileged-mcp-action/v0 and privileged-mcp-action/v1 bundles carry no profile id. For those interpreters the report MUST also carry:

Member	Meaning
`profile_selection`	`default` if `--profile-version` was omitted; `explicit` if it was passed
`input_profile`	JSON `null`
`input_profile_status`	`undeclared_legacy`

These three members are report-shape requirements outside the corpus comparison surface; corpus vectors do not discriminate them.

Consumers MUST NOT infer producer profile, producer release, migration, rollback, or profile provenance from report.profile. Changing --profile-version MAY change the selected interpreter and MUST NOT create evidence of input profile identity.

A future content-bound input profile requires a new profile version. It MUST NOT be retrofitted into frozen v0/v1.

Compatibility classes¶

Canonical bytes. A profile version names the records it recognizes. Additive optional records that stay outside a selected profile's namespace are ignored after bundle integrity. An unrecognized in-namespace payload schema is invalid (fail closed). That exact schema string is retained on the finding as observed_schema, not only in prose. An in-namespace envelope type whose payload declares no schema is also invalid, but observed_schema is omitted so the envelope type is not published as a payload schema.
Claim meaning. v0 and v1 share the v0 claim matrix and report schema assay.privileged_mcp_action.verify.report.v0. Selecting v1 does not change claim vocabulary.
Projections. Report profile is a projection of the selected interpreter. Projection MUST NOT be read as a support window, upgrade path, or producer identity.
Unknown / newer schema. Unknown in-namespace schema stays exit 2, claims absent. The verifier does not upgrade an unknown schema into a verified claim.

Deprecation and support¶

CHANGELOG.md is the single announcement surface. This policy does not promise a rolling pair of releases, and it does not promise support by date.

A released reader MUST be announced deprecated in CHANGELOG.md before the release that stops accepting it. Announcement and removal MUST NOT be in the same release. Between those two releases, acceptance is supported only where a release test exercises that reader. Unexercised historical readers are unsupported, not promised.

Upgrade and rollback remain #2487.

Released 5.4 admits privileged-mcp-action/v0 and privileged-mcp-action/v1 by explicit --profile-version (default v0) as reader admission only. That admission is not input identity, producer identity, producer release, migration, upgrade, rollback, or autodetect.

Migration¶

Migration that changes claim meaning, closed vocabularies, or required identity MUST produce a new profile version rather than rewrite bytes under an existing identifier. This slice does not ship an autodetect or automatic migration engine.

Importer¶

assay evidence privileged-mcp-action is byte-faithful and profile-agnostic. It does not select a profile, does not autodetect one, and does not stamp a profile id onto the bundle. Verification owns profile semantics.