V2: support progressive updates from running tools #35363

Summary

V2 tools need a supported way to publish progress while they are still running, without settling the tool call.

Both execute and shell need this capability. The same capability must be available to tools registered through the plugin API rather than being implemented as a special case for built-ins.

Design work

Define a V2 shape for progressive tool updates, including:

• how a running tool emits text, structured metadata, or other progress updates before its final result
• how updates identify and mutate/project the active tool call
• how plugin-registered tools access the API
• ordering, cancellation, throttling/backpressure, and late-update behavior
• whether progress is durable/replayable or explicitly ephemeral
• how TUI, app, SDK, and event consumers render or observe updates
• parity with useful V1 behavior without carrying its accidental API shape forward

Acceptance criteria

• execute can report meaningful child-call/program progress before completion.
• shell can report ongoing command output/status before completion.
• external tool plugins can use the same supported API.
• the event/projection and client rendering semantics are documented and tested.
• the final tool result/error remains distinct from in-progress updates.

Related

• feat(core): expose deferred tools through execute #35361 — V2 deferred tools through execute
• feat(core): implement V2 session.shell #35183 — V2 shell implementation
• V2: add tool registration to Promise plugins #34489 — V2 plugin tool registration
• V2: align session shell events with Shell service #35018 — V2 shell events/service follow-up

Source: https://discord.com/channels/1391832426048651334/1520962938733723720/1523078773669367919