[DOCS] Subagent continuation docs still show the old resume flow

Issue #35141 Verification

Title: [DOCS] Subagent continuation docs still show the old resume flow
Issue Date: 2026-03-17
Verification Date: 2026-03-18
Status: PARTIALLY RESOLVED

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Issue Summary

This issue reports that subagent continuation documentation still describes the old resume parameter flow for the Agent tool, whereas Claude Code v2.1.77 removed the resume parameter and replaced continuation with SendMessage({to: agentId}). The issue identifies three affected pages: the code.claude.com sub-agents page, the platform.claude.com Agent SDK subagents guide, and the platform.claude.com Agent SDK TypeScript reference.

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Verification Results

Claim 1: code.claude.com sub-agents page still teaches the old resume pattern

Status: RESOLVED
The sub-agents page at https://code.claude.com/docs/en/sub-agents (lines 663-679) has been updated. It now describes the SendMessage-based flow:

• Line 669: "When a subagent completes, Claude receives its agent ID. Claude uses the SendMessage tool with the agent's ID as the to field to resume it."
• Line 679: "If a stopped subagent receives a SendMessage, it auto-resumes in the background without requiring a new Agent invocation."

The page no longer mentions the Agent tool's resume parameter for subagent continuation.
Verdict: The code.claude.com sub-agents page has been updated to reflect the new SendMessage flow.

Claim 2: platform.claude.com Agent SDK subagents guide still describes the old flow

Status: UNRESOLVED
The Agent SDK subagents guide at https://platform.claude.com/docs/en/agent-sdk/subagents (lines 377-478) still teaches the old session-resume pattern:

• Line 385: "Resume the session: Pass resume: sessionId in the second query's options, and include the agent ID in your prompt"
• Line 388: "You must resume the same session to access the subagent's transcript. Each query() call starts a new session by default, so pass resume: sessionId to continue in the same session."
• Lines 426-430 (TypeScript example): Shows options: { ... resume: sessionId } in the second query invocation
• Lines 473-478 (Python example): Shows options=ClaudeAgentOptions(... resume=session_id) in the second invocation

Note: The resume parameter here refers to the SDK-level query() session resume, not the Agent tool's resume parameter. The SDK resume parameter is for resuming an SDK session and is still a valid option. However, the guide's framing implies this is the way to continue a subagent, which may conflict with the new SendMessage approach for agent-level continuation.
Verdict: The SDK subagents guide still describes the session-resume pattern for subagent continuation. Whether this is outdated depends on whether session-level resume is still the recommended SDK-level approach (it remains in the SDK API), but the guide does not mention SendMessage as an alternative.

Claim 3: platform.claude.com TypeScript reference still shows resume?: string in AgentInput

Status: UNRESOLVED
The TypeScript reference at https://platform.claude.com/docs/en/agent-sdk/typescript (lines 1217-1229) still shows:

````

type AgentInput = {
  description: string;
  prompt: string;
  subagent_type: string;
  model?: "sonnet" | "opus" | "haiku";
  resume?: string;
  run_in_background?: boolean;
  max_turns?: number;
  name?: string;
  team_name?: string;
  mode?: "acceptEdits" | "bypassPermissions" | "default" | "dontAsk" | "plan";
  isolation?: "worktree";
};

````

The resume?: string field is still present in the AgentInput type definition.
Verdict: The Agent tool's AgentInput type still documents the resume parameter, contradicting the v2.1.77 changelog which states "The Agent tool no longer accepts a resume parameter."

Claim 4: The SDK-level ClaudeAgentInput still has a resume field

Status: Informational
The SDK-level ClaudeAgentInput at https://platform.claude.com/docs/en/agent-sdk/typescript (line 225) documents resume | string | undefined | Session ID to resume. This is the SDK session-level resume (for resuming a query() session), not the Agent tool's resume parameter. This is a distinct concept and is likely still valid.

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Current State

| Claim | Status |
|-------|--------|
| code.claude.com sub-agents page uses old resume flow | RESOLVED - updated to use SendMessage |
| platform.claude.com SDK subagents guide uses old flow | UNRESOLVED - still shows session-resume pattern |
| platform.claude.com TypeScript AgentInput has resume | UNRESOLVED - still shows resume?: string |

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Suggested Fix

1. Remove resume?: string from the AgentInput type definition on the TypeScript reference page, or add a note that it has been removed as of v2.1.77.
2. Update the SDK subagents guide to clarify the distinction between SDK session-level resume (still valid for query()) and agent-level continuation (now done via SendMessage). Add guidance or examples showing the SendMessage approach for continuing a subagent within a session.

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References

• URL: https://code.claude.com/docs/en/sub-agents
• Lines 663-679: Updated resume section using SendMessage
• URL: https://platform.claude.com/docs/en/agent-sdk/subagents
• Lines 377-478: Still describes the old session-resume pattern for subagent continuation
• URL: https://platform.claude.com/docs/en/agent-sdk/typescript
• Lines 1217-1229: AgentInput type still includes resume?: string
• Line 225: SDK-level ClaudeAgentInput.resume (distinct concept, likely still valid)
• URL: https://code.claude.com/docs/en/changelog
• Line 82: "The Agent tool no longer accepts a resume parameter"
• Line 83: "SendMessage now auto-resumes stopped agents in the background"

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Conclusion & Recommendation

Primary Concern: The code.claude.com sub-agents page has been updated to reflect the SendMessage flow, but the platform.claude.com SDK pages still document the old resume parameter on AgentInput and the old session-resume subagent continuation pattern.
Resolution Status: PARTIALLY RESOLVED
Recommendation: KEEP OPEN
One of three affected pages has been fixed, but the platform.claude.com SDK TypeScript reference and subagents guide still need updates to reflect the removal of the Agent tool's resume parameter and the new SendMessage continuation flow.

Issue #35141 Verification

Title: [DOCS] Subagent continuation docs still show the old resume flow
Issue Date: 2026-03-17
Verification Date: 2026-03-18
Status: RESOLVED

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Issue Summary

This issue reports that the subagent continuation docs still described the old resume parameter flow for continuing a previously spawned agent, even though Claude Code v2.1.77 replaced it with SendMessage({to: agentId}) and added auto-resume behavior for stopped agents.

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Verification Results

Claim 1: Docs still show the old resume parameter as the continuation mechanism

Status: RESOLVED

The sub-agents page now documents SendMessage as the continuation mechanism under the "Resume subagents" section:

When a subagent completes, Claude receives its agent ID. Claude uses the SendMessage tool with the agent's ID as the to field to resume it. To resume a subagent, ask Claude to continue the previous work.

The old resume parameter is no longer shown as the continuation mechanism.

Verdict: The documentation now correctly shows SendMessage as the supported way to continue a previously spawned agent.

Claim 2: Auto-resume behavior for stopped agents is not documented

Status: RESOLVED

The sub-agents page now explicitly documents auto-resume:

If a stopped subagent receives a SendMessage, it auto-resumes in the background without requiring a new Agent invocation.

Verdict: The auto-resume behavior is now clearly documented.

Claim 3: Session-level resume vs agent-level continuation distinction missing

Status: RESOLVED

The documentation now distinguishes between these concepts. Session persistence is documented separately:

Subagent transcripts persist within their session. You can resume a subagent after restarting Claude Code by resuming the same session.

While agent-level continuation uses SendMessage as described above.

Verdict: The distinction between session resume and agent continuation is now clear in the documentation.

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Current State

| Claim | Status |
|-------|--------|
| Old resume parameter shown as continuation mechanism | RESOLVED |
| Auto-resume behavior undocumented | RESOLVED |
| Session vs agent continuation distinction missing | RESOLVED |

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References

• https://code.claude.com/docs/en/sub-agents

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Conclusion & Recommendation

Primary Concern: Subagent continuation docs showed the deprecated resume parameter instead of the current SendMessage mechanism.

Resolution Status: RESOLVED

Recommendation: CLOSE

The sub-agents page now documents SendMessage as the continuation mechanism, describes auto-resume behavior for stopped agents, and distinguishes session-level resume from agent-level continuation.

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.