Continuity Across Tools and Environments
Agents rarely live in one tool. A run may start in an IDE, continue in a chat, hand off to a CI bot, and finish in a code-review UI. This topic covers how to carry identity, context, and state across those boundaries without losing the thread.
Continuity Across Tools and Environments
Real agent runs are multi-hop: IDE → chat → MCP server → CI → review UI. Each hop is a chance to lose the thread. The three things you must carry across every boundary are identity, correlation, and context.
The three things to carry
| Carry | What it gives you | How | | --- | --- | --- | | Identity | RBAC, audit, least privilege | OAuth on-behalf-of, agent managed identity, signed tokens | | Correlation ID | End-to-end tracing | Stable run/thread ID propagated unchanged through every hop | | Context handoff | The receiving tool knows what just happened | Thread reference, plan link, MCP resource handle — never copy-pasted blobs |
If the receiving tool gets a different correlation ID or a different identity than the sending tool, you have two runs, not one. Audit and debugging both collapse.
MCP as the interop layer
The Model Context Protocol exists precisely to solve this problem at the protocol level. An MCP host (the agent) opens a stateful connection to an MCP server (the tool surface) and negotiates capabilities once. From that point on, tools, resources, and prompts are exchanged over a single contract, regardless of which vendor wrote which server.
Why this matters for continuity:
- Stateful sessions mean context isn't re-shipped on every call.
- Standardised capabilities mean a new tool plugs into an existing host without bespoke glue.
- Explicit consent and authorization are built into the protocol, so identity isn't lost at the boundary.
Don't copy-paste context
The lazy way to hand off context is to dump the chat transcript into the next tool's input. Don't:
- It bloats payloads and burns context budget at every hop.
- It can leak secrets into systems that didn't need to see them.
- The receiving tool has no way to verify what it got.
The right way is to pass a reference: a thread ID, an MCP resource URI, or a signed claim. The receiving tool fetches what it needs, under the propagated identity, with audit intact.
Quick check
Quick check
An agent's work moves from the IDE to a CI bot to a code-review UI. What is the simplest mechanism that lets an on-caller trace the whole run later?
Where this shows up on the exam
Expect a multi-tool scenario asking "what breaks at the handoff?". The correct answers cluster around: propagate the correlation ID, use OBO for identity, prefer MCP over bespoke wrappers, and pass references not payloads. Anything that involves a shared admin account or a new ID per hop is the wrong answer.
Key terms
- Correlation ID
- A stable identifier propagated across every tool, environment, and log so that all activity for one run can be reconstructed end-to-end.
- Context handoff
- The act of passing the relevant slice of agent state from one tool or environment to another — usually as a thread reference, plan link, or signed token.
- MCP server
- A Model Context Protocol server that exposes tools, resources, and prompts to an agent host over a standardised stateful connection — the canonical interop layer for cross-tool context.
- Identity propagation
- Carrying the user's (or agent's) identity across hops via OAuth on-behalf-of, agent managed identity, or signed tokens — so each tool authorises against the same principal.
Common pitfalls
- Generating a new correlation ID at each hop: you fragment the trace into orphan runs and lose end-to-end visibility.
- Copy-pasting context between tools instead of passing a reference: secrets leak into logs, payloads bloat, and the receiving tool can't verify what it got.
- Re-authenticating at each hop as a generic service account: you lose the user identity, which breaks RBAC, audit, and on-behalf-of authorisation.