ACDP OpenTelemetry Attributes

Span attribute names for tagging telemetry with ACDP identifiers, so observability tools can link a span to the signed body it produced or consumed. All names live in the acdp. namespace. Instrumentation such as agent-SDK hooks, the MCP signing proxy (RFC-ACDP-0019) or registry clients SHOULD use these names and types rather than inventing their own.

Rules for this registry.

These attributes are telemetry only. They never enter a body, a signature or a content_hash, and a consumer MUST NOT treat a span attribute as evidence. The signed body and its receipt are the evidence; the attribute only points at them.
A name's meaning and type never change. A changed meaning mints a new name, and the old one becomes Deprecated.
Values are copied verbatim from the wire, with no reformatting: acdp.ctx_id carries the exact ctx_id string, and so on.
Instrumentation MUST NOT put body content, data payloads or the RFC-ACDP-0019 salt in an attribute. Those may be confidential even when the identifiers are not.
Attributes go on the span that did the work: the span that published a body, or the span that consumed a verified one. A span that consumes several bodies uses the array forms.

Producer-side attributes (a span that published a body)

Attribute	Type	Status	Value
`acdp.ctx_id`	string	Provisional	The published body's `ctx_id`
`acdp.lineage_id`	string	Provisional	Its `lineage_id`
`acdp.version`	int	Provisional	Its `version`
`acdp.content_hash`	string	Provisional	Its `content_hash`
`acdp.producer`	string	Provisional	Its `agent_id` (the producer DID)
`acdp.registry`	string	Provisional	Its `origin_registry`
`acdp.type`	string	Provisional	Its `type`
`acdp.derived_from`	string[]	Provisional	Its `derived_from` `ctx_id`s, in body order
`acdp.publish.error`	string	Provisional	When the publish failed: the RFC-ACDP-0007 §5 error code, or `transport` when no ACDP error came back. Absent on success

Consumer-side attributes (a span that used bodies as input)

Attribute	Type	Status	Value
`acdp.input.ctx_ids`	string[]	Provisional	The `ctx_id`s the span consumed
`acdp.input.verified`	boolean	Provisional	`true` only when every consumed body passed producer-signature verification (RFC-ACDP-0001 §5.8) and none was retracted at use time
`acdp.input.chain_verdict`	string	Provisional	When the consumer ran RFC-ACDP-0017 chain verification: the verdict's `chain.latest` value, verbatim (e.g. `ok_with_caveats`)
`acdp.input.chain_verdict_as_of`	string	Provisional	With a sealed-as-of run: the verdict's `chain.as_of` value, verbatim
`acdp.input.verdict_digest`	string	Provisional	That verdict's `verdict_digest`, so the span points at the exact verdict object

Status

Every entry is Provisional until two independent instrumentations emit it. Registry Status values are defined in README.md.