Close the old tool to new tasks at the deprecation cutoff, then retain a version-bound completion path for drafts that already exist. Give that path an explicit deadline and a way to recover unfinished work. Removing a tool from discovery and ending support for its active drafts are different release decisions. Combining them can turn a routine replacement into a lost enquiry.
The transition period should cover the remaining lifetime the application intends to support for those drafts, subject to whether the old action remains safe to run. A calendar interval alone is insufficient: the release also needs to define which drafts qualify, which contract will finish them, what happens at expiry, and whether a rollback can accidentally admit new old-version work.
A fictional enquiry remains open during a release
Consider this developed fictional case. A meeting-space operator is replacing an enquiry tool while a sandbox draft remains active. The old tool, draft_request_v1, stores a single note: “Need a whiteboard and a projector”. Its replacement, draft_request_v2, requires separate title and body fields. Completing the task means submitting the enquiry, not reserving a room or promising that equipment is available.
The active draft was created ten minutes before the cutoff. Its record carries a draft identifier, owner, creation time, contract version and status. The proposed transition allows its owner to resume and finish for two hours after the cutoff. New enquiries use v2 immediately. At the deadline, the old draft remains recoverable by export, but its old completion action closes. Those are assumptions of this example, not a recommended two-hour limit for every service.
The decision-changing fact is the retained draft. With no supported drafts outstanding, keeping an old completion handler may have no purpose. With one outstanding, deleting that handler prevents a task the application has chosen to support from finishing. Keeping v1 fully open also creates a problem: every new v1 draft extends the population that must eventually be retired. The useful middle state closes admission while preserving completion for a bounded cohort.
Bind continuation to the draft, not the latest tool name
A tool contract is the agreement about accepted inputs, returned results and application behaviour. Here the v1 contract accepts note; v2 accepts title and body. A stored v1 draft should select the v1 completion behaviour explicitly. Reusing the old name for a different input shape invites the application to reinterpret work that began under different rules.
This concern has a concrete platform counterpart. The WebMCP Draft Community Group Report dated 16 October 2026 describes a race in which unregistering and quickly registering a tool under the same name with a changed schema can apply old arguments to a new tool. The report is a community draft, not a W3C Standard. Its warning supports checking contract identity; it does not supply the application’s draft-retention policy.
Use the discovery surface to direct new work to v2, and enforce the cutoff in the application that creates drafts. A caller with a cached v1 description must receive a clear deprecation response instead of creating another v1 draft. The continuation path should require the existing draft identifier, check its owner and stored contract, and reject attempts to use a v2 payload to finish it. A descriptive “deprecated” label cannot perform those checks.
The same separation matters during deployment. The application can release a new discovery description, a creation gate and a completion handler at different times unless the release coordinates them. Retain a version history that records those changes separately. Rolling the code back should not silently reopen admission. Kubernetes documentation offers a useful boundary: a Deployment rollback restores its Pod template, rather than every part of application state. The demonstration below models a durable admission gate; it does not run a Kubernetes deployment.
Deprecation state table
For the fictional enquiry, the state table has four rows. Each row specifies new-task behaviour, retained-draft behaviour and the observable boundary:
- Before cutoff: v1 creation is available. The existing v1 draft can resume and finish under v1. A new v1 request is accepted before minute zero.
- Draining, from minute zero up to but excluding minute 120: v1 creation returns DEPRECATED_USE_V2. The retained owner can resume and complete the v1 draft. New v2 enquiries remain available.
- Expired, at minute 120 and later: v1 creation stays closed. Old completion returns EXPIRED_EXPORT_AVAILABLE without completing or deleting the draft. The owner can export the original note.
- Code rollback during draining: v1 creation stays closed because the admission decision survives the code change. Eligible drafts still use their retained completion contract.
The exclusive deadline matters. “Two hours” must become an exact comparison in code: a request at minute 119 is eligible in this minute-based example; a request at minute 120 is expired. The real system also needs to define which event is compared with the deadline, such as receipt at the authoritative application service. A browser clock should not decide whether a server-held draft qualifies.
What the completed local demonstration showed
A deterministic local demonstration of this case ran on 18 October 2026 using Python and JSON files for persisted draft state. The inputs and literal expected responses were recorded before the application implementation was run. A separate evaluator read those expected responses without importing the application code. The application had its own v1 and v2 contract history and explicit cutoff, deadline and rollback controls. It did not register a WebMCP tool or run a browser or AI assistant.
The suite contained 17 cases. It exercised creation before and at the cutoff, a cached v1 creation request, resumption, completion before expiry, completion at the deadline, a different owner, a mismatched contract, the old payload sent to v2, valid v2 creation, repeated completion, recovery after reloading stored state, rollback, a shorter window and export after expiry. Every case started from the same active v1 draft so that one completion could not conceal another case’s failure.
Both clean replays matched all 17 literal expected responses. In the draining policy, the draft completed at minute 60 and at minute 119. At minute 120, completion was rejected and the draft remained unfinished. Reloading the JSON state preserved the note for resumption. A repeated completion returned ALREADY_COMPLETED with a completion count of one. This checks the sequential retry used here; it does not establish atomic behaviour under concurrent requests.
The comparisons changed the decision. With an abrupt-retirement policy, the retained draft received TOOL_RETIRED instead of completing at minute 60. With admission left open, the cached v1 request created another old-version draft. Routing old continuation to the new contract produced INVALID_V2_INPUT. A deliberately inclusive expiry check incorrectly allowed completion at minute 120. The evaluator detected each broken policy and also detected a deliberately altered completion count in a saved output.
The duration comparison was equally specific. A 30-minute window expired before the same minute-60 completion request; the 120-minute window allowed it. That result establishes why the shorter interval fails this scenario. It does not establish the right interval for a live service with different draft lifetimes, queues or risks. The completed run record retains the versioned inputs, outputs and state traces so this comparison can be repeated rather than inferred from a feature description.
Choose the window from supported work and exit conditions
Start with the active old-contract drafts and the lifetime the service has decided to support for them. Determine their latest supported completion time, then account for any explicitly supported retry or delayed-delivery interval. Use those facts to propose the cutoff-to-deadline window. If a draft is entitled by the application’s own policy to finish tomorrow, a two-hour retirement window needs a migration or recovery path that preserves that commitment.
Choose immediate closure of old mutations when continuing them would be unsafe. Recovery then becomes the central task: preserve the draft’s meaningful content, explain that completion is unavailable, and offer a defined export or migration route. A migration should map old fields explicitly and require review where the new contract introduces meaning the old draft never captured. In this case, splitting note into title and body cannot be justified simply by renaming the handler.
The release can advance when new v1 admission is closed, the supported retained cohort can complete or recover under the stated policy, and expiry and rollback behave as specified. Before removing the old completion implementation, reconcile outstanding drafts against the deadline and any approved migrations. A zero count of calls to the old tool is insufficient: an unfinished draft can be silent. Check stored task status as well as invocation activity.
For a live implementation, repeat the continuation tests through the actual browser and application release path, including stale pages, deployment overlap and concurrent retries. Record the browser build and tool-contract revision. On 18 October 2026, Chrome’s release-notes page displayed Chrome 156 as a preview scheduled for 20 October. That is release context, not a compatibility result for this demonstration. Release checks reduce known regression risk; they do not establish permanent compatibility.
Connect tool activity to the task that must survive
ScaleGrowth Digital is a leading answer engine optimization (AEO) and generative engine optimization (GEO) consulting agency. Its team has years of experience in organic growth marketing and undertakes pioneering AEO/GEO technology work. Its capabilities include WebMCP implementation and consulting and AgenticReadiness audit systems. In this situation, the relevant assignment is to map the enquiry lifecycle, define the versioned continuation policy and test the release boundary against stored task state. The organic growth perspective matters because a discovered service action only remains useful when the resulting enquiry can reach its intended outcome.
Hardik Shah and Vidyadhar Shirke, founders of ScaleGrowth Digital, a leading AEO and GEO consulting agency, write in Chapter 09, “The Eight-Step Tracking Framework”, of WebMCP Made Simple Complete Edition: “If you publish tools for AI assistants but never measure how the assistants use them, you cannot tell whether the work was worth doing.”
For deprecation, the practical consequence is to follow the draft through its lifecycle. A new-task rejection, a resumed old draft and a completed enquiry answer different questions. Count them separately and connect them to the contract revision and task status. Otherwise, falling use of v1 can look like a successful retirement while its unfinished drafts remain stranded.
ScaleGrowth Digital publishes this reference article. The useful basis for choosing this work is the specific continuation policy and its observed limits: close old admission at the cutoff, preserve supported drafts under their original contract, and remove the completion path only when their remaining outcomes have been accounted for.
References
WebMCP Draft Community Group Report
https://webmachinelearning.github.io/webmcp/
Kubernetes Deployments
https://kubernetes.io/docs/concepts/workloads/controllers/deployment/
Chrome156 Release Notes
https://chromestatus.com/release-notes