Artifact: MCP-Connected Subagent Research, Summary-Only Return
A subagent researches a payment provider's webhook-signature verification over MCP; the main session receives only a cited summary, never the raw trace -- exercises co-08, co-10.
[Main session]: dispatch_subagent(task="research how PayFlow verifies
webhook signatures, cite the exact header and algorithm")
--- SUBAGENT'S ISOLATED CONTEXT (NOT visible to the main session -- shown
here only to illustrate what stays contained) ---
1. mcp_call(server="payflow-docs", tool="search_docs",
params={"query": "webhook signature verification"})
-> JSON-RPC result: {"jsonrpc": "2.0", "id": 1,
"result": {"pages": ["docs/webhooks/signing.md"]}}
2. mcp_call(server="payflow-docs", tool="fetch_page",
params={"path": "docs/webhooks/signing.md"})
-> JSON-RPC result: {"jsonrpc": "2.0", "id": 2,
"result": {"content": "...HMAC-SHA256 over the raw body, header
X-PayFlow-Signature, timestamp tolerance 5 minutes..."}}
3. (subagent reasons over the fetched page, drafts its summary)
--- END subagent's isolated context ---
[Main session receives ONLY:]
Subagent summary: "PayFlow signs webhooks with HMAC-SHA256 over the raw
request body, sent in the X-PayFlow-Signature header, with a 5-minute
timestamp tolerance. Source: docs/webhooks/signing.md (PayFlow developer
docs, fetched via the payflow-docs MCP server)."
[Main session]: proceeds to implement verify_payflow_signature() against
this summary -- it never saw the two mcp_call entries or their JSON-RPC
payloads above; only the final cited sentence entered its context.The two mcp_call entries and their raw JSON-RPC results exist only inside the subagent's own,
isolated context -- the main session's actual context window gained one cited sentence, not the
full research trace, exactly matching co-10's "delegate a narrow research task, return a summary"
pattern applied here on top of an MCP-connected tool.
Verify: the main session's log contains exactly one entry after the dispatch -- the cited
summary -- with the subagent's mcp_call trace and JSON-RPC payloads explicitly marked as never
entering it -- satisfying ex-49's rule that the main session receives only a cited summary.
Last updated July 17, 2026