A2A server ignores the profile's input member, so 3.2 JS clients' requests arrive empty (9.6.1, and next) #1887

Observed

On adcp 9.6.1, the A2A executor reads an invocation DataPart's parameters member only (a2a_server.py, the data.get("parameters", {}) calls in the skill parser and _parse_skill_from_message). A client that follows the AdCP v3 A2A profile sends { "skill": ..., "input": { ... } }, so the task handler receives {}.

@adcp/sdk 16.7.0 (the adcp-3.2 dist-tag) sends input whenever the agent card's A2A protocolVersion is not 0.x. Against a 9.6.1 server, every A2A call from that client loses its request:

• get_adcp_capabilities succeeds but doesn't echo context, so the storyboard capability_discovery steps fail with "Response echoes back the context object at /context".
• Versioned tools fail with VERSION_UNSUPPORTED: adcp_version is required, because adcp_version was in the dropped input.

The same calls over MCP pass.

Expected

The A2A profile (docs/building/by-layer/L0/a2a-profile-extension.mdx) defines input as the required member: "parameters is not an alias for input in this profile". A 3.2-line server should dispatch input to the handler and echo its context.

10.0.0b13 lists input in _DATA_MEMBERS, but its default parser still reads parameters (lines 626, 640 and 1137). #1659's description notes the gap: "The default parser reads parameters but not the A2A profile's input member. This is a separate issue." This is that issue.

Ask

1. Read input in the default A2A parser on next.
2. Backport to 9.x so 3.2 servers interoperate with the 3.2 JS client.

Accepting parameters from clients that don't activate the profile (A2A 0.x) keeps older callers working.

Reproduction

Serve any DecisioningPlatform with 9.6.1 over A2A, then:

npx -y @adcp/sdk@16.7.0 storyboard run http://localhost:8000/ --protocol a2a (storyboard capability_discovery)

Impact

The embedded sales agent (scope3data/embedded-sales-agent) can't move its blocking storyboard gate off @adcp/sdk 12.1.1 (AdCP 3.1) once it stops serving 3.1. Our 3.1 removal is waiting on this.