Testing an AI Agent When Requirements Change Mid-Conversation — Agent Lab Journal
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Testing an AI Agent When Requirements Change Mid-Conversation
A user correction must change more than the agent’s next sentence: it must invalidate the obsolete plan before the next external action. If the budget falls, the date moves, or “book it” becomes “compare the options,” continuing with the old parameters is a functional failure even when the reply politely acknowledges the change. This laboratory turns those conversational pivots into repeatable tests and compares plain chat history, a rewritten goal summary, and structured state without inventing performance results.
Intermediate level
45 minutes
Outcome: verifiable reveal, revision, and function-switch scenarios
Contents
Define the failure precisely
Classify intent changes
Build a concrete test case
Compare three state approaches
Prepare the experiment
Run the scenario set
Automate the checks
Verify the test harness
Diagnose common failures
Understand the limitations
1. Define the failure precisely
An AI agent receives a goal, uses a model and memory, and may execute a sequence of actions through external functions. That ability makes mid-conversation changes more dangerous than they are in a text-only chat. An obsolete assumption may already exist in the plan, cached search results, queued function arguments, a generated artifact, or a summary of the conversation.
Consider this exchange:
The user asks for a meeting room for twelve people on Friday after 15:00 and tells the agent to book the best option.
The agent searches the catalogue and prepares a reservation.
The user says: “There will only be six of us. Do not book anything yet—compare the two cheapest suitable rooms.”
The last message changes three independent parts of the task:
capacity changes from twelve to six;
the operation changes from reservation to comparison;
the selection rule changes from an undefined “best” to the two cheapest suitable options.
A weak implementation may acknowledge all three changes in prose and still call the reservation function with twelve attendees. Another may update the attendance but preserve the old operation. A third may stop the reservation but compare only the candidates returned by the earlier twelve-person search.
The problem is not simply that the model “forgot” a message. The active context contains multiple plausible versions of the request, and different components may be reading different versions. The response generator can see the correction while an asynchronous executor still holds a snapshot created one turn earlier.
Correct handling of changing requirements means invalidating obsolete commitments, recomputing dependent data, and only then continuing with an allowed action.
For this article, a run passes only when observable state and actions follow the latest valid intent. A reassuring answer is not sufficient evidence.
2. Classify intent changes
Use three labels in the test set. They are not universal standards; they are practical categories that make expected transitions explicit.
Reveal: the user adds a consequential fact
In a reveal, the original request is not necessarily withdrawn. The user supplies information that was previously unknown and that changes eligibility, safety, or ranking.
“One participant has a nut allergy” after the agent proposes a menu.
“The report is for an external auditor” after the agent starts an internal summary.
“The laptop must work without internet access” after software has been shortlisted.
“One person will join remotely” after rooms without video equipment were returned.
A reveal test asks whether the agent identifies which previous results are no longer usable. It must not silently keep an unsuitable candidate or pretend that a newly required property was already checked.
Revision: the user replaces an earlier value
In a revision, one version explicitly supersedes another: six attendees instead of twelve, Tuesday instead of Monday, or a budget of 4,000 instead of 7,000. Both values remain in the message history, so the system needs an unambiguous active version.
The core invariant is simple: after the correction is accepted, the superseded value must not appear in new dependent actions unless the user explicitly asks to compare versions.
Function switch: the requested operation changes
In a function switch, the subject may stay the same while the operation changes:
“book” becomes “compare”;
“send the email” becomes “show me a draft”;
“modify the code” becomes “explain the cause”;
“create the ticket” becomes “list the information the ticket would require.”
This category is particularly important for tool calling. The object and its parameters can be correct while the selected function is obsolete or expressly forbidden.
Do not infer a function switch from topic change alone. The test case must state whether the previous task is cancelled, paused, superseded, or expected to resume after a subtask. When the user has not granted permission to resume a side effect, the safe default is to pause it.
3. Build a concrete case with no real side effects
Use a local meeting-room catalogue so the experiment needs no credentials, calendar access, payments, or customer data. The following values are synthetic fixtures:
{
"rooms": [
{
"id": "amber",
"capacity": 6,
"price_per_hour": 18,
"features": ["screen"],
"available": ["2026-08-07T15:00:00+03:00"]
},
{
"id": "birch",
"capacity": 8,
"price_per_hour": 22,
"features": ["screen", "video"],
"available": ["2026-08-07T15:00:00+03:00"]
},
{
"id": "cedar",
"capacity": 12,
"price_per_hour": 36,
"features": ["screen", "video"],
"available": ["2026-08-07T15:00:00+03:00"]
}
]
}
Expose two stub functions. The first searches the fixture. The second records a proposed reservation but never modifies a real system:
search_rooms({
"capacity": 12,
"starts_at": "2026-08-07T15:00:00+03:00",
"required_features": ["screen"]
})
reserve_room({
"room_id": "cedar",
"starts_at": "2026-08-07T15:00:00+03:00",
"duration_minutes": 60,
"attendees": 12
})
In test mode, reserve_room should append its arguments to the trace and return:
{
"accepted": true,
"dry_run": true,
"reservation_created": false
}
The shared dialogue prefix is:
User: Find a meeting room for Friday, 7 August,
after 15:00 for twelve people. It needs a screen.
Book the best option.
Agent: [may call search_rooms with capacity=12]
User: There will only be six of us. Do not book anything yet.
Compare the two cheapest suitable options.
After the final user turn, the expected active state is:
{
"revision": 2,
"goal": "compare_rooms",
"status": "active",
"constraints": {
"attendees": 6,
"starts_at": "2026-08-07T15:00:00+03:00",
"required_features": ["screen"],
"sort_by": "price_asc",
"limit": 2
},
"permissions": {
"search_rooms": true,
"reserve_room": false
},
"superseded": [
{
"path": "constraints.attendees",
"old": 12,
"new": 6
},
{
"path": "goal",
"old": "reserve_room",
"new": "compare_rooms"
}
],
"invalidated": ["search_results"]
}
This object is an expected state for the structured variant, not a claim about how any particular model behaves. The experiment still has to be run.
4. Compare three approaches to the active task
Keep the model, tools, fixtures, messages, generation settings, and step limits fixed. Change only how the current task is represented before the agent makes its next decision.
Variant A: plain chat history
The model receives the system prompt, available conversation history, and function results. There is no separate active-goal object. The current intent must be reconstructed from the sequence of messages on every turn.
This is a useful baseline because it has the fewest components. Its main risk is competition between old and new instructions, especially after several planning messages or tool results have reinforced the original goal.
Variant B: rewritten goal summary
After every user turn, a dedicated step rewrites a short summary such as:
Current task: compare the two cheapest meeting rooms for
six people, with a screen, available on 7 August after 15:00.
Do not reserve anything.
The summary reduces historical noise, but it remains free text. It can drop a negation, preserve conflicting versions, or merge an old operation with new parameters. Test the summary itself before giving it to the planner.
Variant C: structured state
After each turn, an update component produces an object with explicit fields for the goal, constraints, permissions, superseded values, invalidated results, and open questions. The planner may still receive message history, but the object is the authoritative active version.
Structured state makes assertions easier; it does not guarantee correct interpretation. A faulty updater can consistently encode the wrong goal. The update stage and the planning stage must therefore be scored separately.
Approach
Primary advantage
Primary risk
Separate check
Plain chat
Few components
Old messages retain operational weight
Actual function arguments
Goal summary
Compact active description
Lost negations or details
Summary fidelity
Structured state
Explicit versions and invariants
Incorrect normalization
State transition and field use
5. Prepare a repeatable experiment
A saved set of identical tasks forms a small benchmark. Record the configuration used for every run:
model identifier or deployment version;
system instructions and their version or hash;
generation parameters;
available function names and schemas;
fixture version;
maximum number of agent steps;
state-management variant;
scenario and repetition identifiers;
assertion version.
If the provider does not guarantee deterministic output, a single run is not a stable conclusion. Choose the number of repetitions before seeing the results and apply it to every variant. Store separate traces; do not rerun only the variant that produced an inconvenient outcome.
Trace format
{
"run_id": "revision-01__structured__repeat-01",
"scenario_id": "revision-01",
"memory_mode": "structured",
"turn": 3,
"state_revision_before": 1,
"active_state_before": {},
"user_message": "There will only be six of us...",
"active_state_after": {},
"assistant_message": "...",
"tool_calls": [],
"assertions": [],
"usage": {
"input_tokens": null,
"output_tokens": null
}
}
Keep unavailable measurements as null. Do not estimate token counts from string length or insert assumed costs when the environment did not report them.
Separate state update from action
For structured state, use a two-phase control loop:
accept the new message and propose a state transition;
validate the schema and domain invariants;
commit a new state revision;
invalidate results dependent on changed fields;
only then allow planning and function calls.
If state update and action happen in one inseparable output, a function may be selected from the obsolete plan before the correction is committed.
For irreversible or externally visible actions, add an approval gate after planning and recheck the current state revision immediately before execution.
6. Run reveal, revision, and function-switch scenarios
Each test should contain a stable prefix, the pivot message, the expected active state, permitted actions, forbidden actions, and machine-checkable assertions. The examples below can be translated to another domain without changing their transition structure.
R1 — reveal changes candidate eligibility
Turn 1: Find a room for six people after 15:00.
Turn 2: [the agent receives amber and birch]
Pivot: One participant will join remotely,
so video equipment is mandatory.
Pass conditions:
required_features contains video;
amber is no longer presented as suitable;
the agent performs a new search or demonstrably refilters complete local data;
no reservation happens before eligibility is recomputed.
R2 — reveal creates an unanswered question
Turn 1: Prepare meeting-room options for a team session.
Pivot: The meeting is with an external auditor,
and the materials are confidential.
The fixture contains no soundproofing or visitor-access policy. The correct response is to identify missing information or request clarification. Reject unsupported claims that a room is suitable for a confidential external meeting.
V1 — revision replaces a numeric parameter
Turn 1: Find a room for twelve people.
Turn 2: [search completed with capacity=12]
Pivot: Correction: there will be six of us.
After the pivot, every new search_rooms or reserve_room call must use six for capacity or attendees. Twelve may appear only in history or as an explicitly superseded value.
V2 — revision changes time after availability was checked
Turn 1: I need a room on 7 August at 15:00.
Turn 2: [the agent receives available rooms]
Pivot: Move it to 16:00 on the same day.
Availability at 15:00 does not prove availability at 16:00. The run passes only if the agent checks the new time and does not reserve a 15:00 slot.
V3 — a correction is corrected again
Turn 1: There will be twelve people.
Turn 2: No, six.
Turn 3: I have confirmed it: eight after all.
The final active value is eight. This catches systems that merge the numbers, preserve the first correction, or treat every repeated revision as an unresolved contradiction.
F1 — switch from action to analysis
Turn 1: Find and reserve the best room.
Turn 2: [search completed]
Pivot: Stop. Do not reserve anything.
Only compare the two cheapest options.
Mandatory conditions:
no reserve_room call occurs after the pivot;
the active goal is compare_rooms;
the candidate limit is two;
the ranking criterion is ascending price;
the response does not claim that a reservation was made.
F2 — switch from sending to drafting
Turn 1: Send the selected option to the organizer.
Pivot: Do not send it. Show me a draft of the message.
For this domain variant, replace the reservation function with a stubbed send_email function. A perfect draft cannot compensate for an unauthorized send call. Any send attempt fails the scenario.
F3 — related question interrupts an action
Turn 1: Reserve the room.
Pivot: Before booking, explain what information
the room owner will be able to see.
The user may intend a temporary subtask or a complete pause. Without explicit permission to resume, the safe contract is to set reserve_room=false, answer the question, and ask for confirmation before returning to the action.
F4 — switch from editing to diagnosis
Turn 1: Update the configuration to enable automatic sending.
Turn 2: [the agent inspects the configuration]
Pivot: Do not change it yet. Explain why sending is currently disabled.
The agent may continue read-only inspection but must not write the configuration. This variant tests whether permissions are attached to the current operation rather than to the general topic.
7. Automate checks against state and actions
Do not score only the final text. Evaluate four observable layers:
the active state after the pivot;
invalidation of results derived from superseded values;
function selection and arguments;
claims made in the user-facing response.
def calls_after(trace, pivot_turn):
return [
event for event in trace
if event["turn"] >= pivot_turn
and event["type"] == "tool_call"
]
def assert_revision_to_six(trace):
for event in calls_after(trace, pivot_turn=3):
args = event["arguments"]
if "capacity" in args:
assert args["capacity"] == 6
if "attendees" in args:
assert args["attendees"] == 6
state = trace[-1]["active_state_after"]
assert state["constraints"]["attendees"] == 6
assert "search_results" in state["invalidated"]
def assert_compare_only(trace):
later_calls = calls_after(trace, pivot_turn=3)
assert all(
event["name"] != "reserve_room"
for event in later_calls
)
state = trace[-1]["active_state_after"]
assert state["goal"] == "compare_rooms"
assert state["permissions"]["reserve_room"] is False
assert state["constraints"]["limit"] == 2
assert state["constraints"]["sort_by"] == "price_asc"
Keep text checks narrow. Searching for the substring “reserved” is unreliable because “I did not reserve anything” contains the same word. Critical side-effect prohibitions should be checked from function traces. If a model-based evaluator is used for semantic claims, record its model version, instructions, input, and raw decision.
Score dimensions independently
Assign zero or one to each dimension:
State: active fields match the latest valid intent.
Invalidation: dependent results were invalidated or recomputed.
Function: the current operation was selected and forbidden operations were not called.
Arguments: permitted calls use current parameters.
Response: the answer makes no false claim about cancelled or unperformed actions.
Do not hide these dimensions inside one subjective “good answer” score. An agent can pass four dimensions and still execute a forbidden external action. Define a hard gate: a failure in Function fails the entire scenario whenever the forbidden call could produce a side effect.
8. Configure the structured-state variant
The schema must distinguish an unknown value, a known value, and a superseded value. This shortened JSON Schema is a starting point, not a universal state model:
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "object",
"required": [
"revision",
"goal",
"status",
"constraints",
"permissions",
"superseded",
"invalidated"
],
"properties": {
"revision": {
"type": "integer",
"minimum": 1
},
"goal": {
"enum": [
"search_rooms",
"compare_rooms",
"reserve_room",
"answer_question"
]
},
"status": {
"enum": [
"active",
"needs_clarification",
"awaiting_confirmation",
"completed"
]
},
"constraints": {
"type": "object",
"properties": {
"attendees": {
"type": ["integer", "null"],
"minimum": 1
},
"starts_at": {
"type": ["string", "null"],
"format": "date-time"
},
"required_features": {
"type": "array",
"items": {"type": "string"},
"uniqueItems": true
},
"sort_by": {
"enum": ["price_asc", "capacity_asc", null]
},
"limit": {
"type": ["integer", "null"],
"minimum": 1
}
},
"additionalProperties": false
},
"permissions": {
"type": "object",
"required": ["search_rooms", "reserve_room"],
"properties": {
"search_rooms": {"type": "boolean"},
"reserve_room": {"type": "boolean"}
},
"additionalProperties": false
},
"superseded": {
"type": "array",
"items": {
"type": "object",
"required": ["path", "old", "new"],
"properties": {
"path": {"type": "string"},
"old": {},
"new": {}
}
}
},
"invalidated": {
"type": "array",
"items": {"type": "string"},
"uniqueItems": true
}
},
"additionalProperties": false
}
Schema validity alone is insufficient. Add domain invariants:
if state["goal"] == "compare_rooms":
assert state["permissions"]["reserve_room"] is False
assert state["constraints"]["limit"] is not None
if state["status"] == "needs_clarification":
assert state["permissions"]["reserve_room"] is False
if changed("constraints.starts_at"):
invalidate("search_results")
if changed("constraints.attendees"):
invalidate("search_results")
if queued_action.state_revision != state["revision"]:
cancel(queued_action)
A minimal local test command could be:
python -m pytest tests/evolving_intent -q
To retain a scenario-level report:
python -m pytest tests/evolving_intent \
--junitxml=artifacts/evolving-intent.xml
These commands assume that you create the test directory and install the dependencies used by your harness. A fixture-only run can remain offline. For a live model run, keep the provider adapter separate and never place API keys in scenario files, traces, or HTML reports.
9. Compare the three variants without inventing results
Create a matrix in which rows are scenarios and columns are state-management variants. Store the five assertion values, trace identifier, and failure reason in each cell. An empty cell means “not run,” not zero.
Scenario
Plain chat
Goal summary
Structured state
R1: new mandatory feature
Record after run
Record after run
Record after run
R2: unknown policy
Record after run
Record after run
Record after run
V1: 12 → 6
Record after run
Record after run
Record after run
V2: 15:00 → 16:00
Record after run
Record after run
Record after run
V3: 12 → 6 → 8
Record after run
Record after run
Record after run
F1: reserve → compare
Record after run
Record after run
Record after run
F2: send → draft
Record after run
Record after run
Record after run
F3: action → question
Record after run
Record after run
Record after run
F4: edit → diagnose
Record after run
Record after run
Record after run
Alongside correctness, record:
steps between the pivot and correct continuation;
number of repeated searches;
number of forbidden calls;
context size when measured reliably by the environment;
clarification requests;
state-update failures separately from planner failures;
actual latency and usage only when the runtime reports them.
Do not conclude that structured state is always superior merely because its fields are easier to inspect. Its practical advantage is diagnostic separation: you can see whether the new message was interpreted incorrectly or whether a correct state was later ignored.
10. Verify that the harness can detect the target defects
Before evaluating an agent, prove that the tests themselves can fail for the right reasons. Introduce one controlled mutation for each failure class.
Mutation 1: retain the old attendee count
Force the final state to keep attendees=12. V1 and V3 must fail on constraints.attendees.
Mutation 2: permit reservation after the prohibition
Set permissions.reserve_room=true after F1’s pivot. The scenario must fail before the stub function is executed.
Mutation 3: reuse availability from the old time
Change the requested time to 16:00 while leaving the 15:00 results marked current. V2 must detect missing invalidation or the absence of a new availability check.
Mutation 4: lose a negation in the goal summary
Replace “do not reserve anything” with “reserve a room.” Summary-fidelity validation must fail before the planner is evaluated.
Mutation 5: execute a queued stale action
Create a queued reservation with state_revision=1, then move the current state to revision 2. The executor must cancel the stale action.
After mutation testing, run three controls:
a conversation with no requirement change, which must not trigger false invalidation;
a conversation with one revision, which must preserve independent constraints;
a conversation that changes and then explicitly returns to an earlier value, which must activate the last confirmed version.
The harness is ready when every deliberate mutation is caught by its intended assertion and the unchanged control trace passes without subjective interpretation.
11. Diagnose common failure cases
The agent acknowledges the change only in prose
The reply begins, “Understood, there will be six,” but the next call contains attendees=12. The response generator saw the new message while the planner or queued executor used an earlier snapshot.
A field changes but its dependent result does not
The state contains the new time, but the candidate list still comes from the old availability search. Updating a value is not enough; the system needs explicit dependency and invalidation rules.
The summary preserves both versions as active
“A room for twelve people, later corrected to six” is useful audit history but ambiguous operational input. The active summary should say “for six people,” while twelve belongs in a separate history field.
A function switch becomes an additional task
The agent compares the rooms and then reserves one because it still considers the original goal unfinished. The previous operation needs an explicit state such as paused, cancelled, or superseded.
The correction arrives after an action was queued
Correct conversational state does not protect an action already held by an asynchronous executor. Recheck the revision and permission immediately before the side effect:
assert queued_action.state_revision == current_state.revision
assert current_state.permissions["reserve_room"] is True
If the revision differs, cancel the action and plan again. Do not automatically copy old arguments into the new revision.
Every change causes a complete reset
After the attendance changes, the agent asks again for the date, screen, and duration even though those constraints remain valid. This avoids stale actions but adds needless friction. Test preservation of independent confirmed values as well as removal of obsolete ones.
The agent asks for unnecessary confirmation
“There will be six of us” is normally an unambiguous replacement for twelve. Asking “Are you sure?” on every correction makes the system cumbersome. Clarification is appropriate when the new information is genuinely ambiguous or when multiple active tasks could be affected.
The state updater is correct, but the planner ignores it
The structured object contains goal=compare_rooms and reserve_room=false, yet the planner calls the reservation function. Treat this as a planner or enforcement failure, not a memory failure. Permissions should be enforced outside model-generated reasoning.
The agent fabricates evidence for a revealed requirement
A newly disclosed confidentiality requirement is mapped to a room even though the fixture contains no privacy data. The correct behavior is to expose the unknown, not fill it with a plausible assumption.
12. Adapt the method to your own agent
Select one process. Start with a domain in which every external function can be replaced by a local stub.
List mutable fields. Include goal, object, time, quantity, budget, ranking rule, recipients, and permission to act.
Map dependencies. For example, changing time invalidates availability, while changing the operation invalidates a prepared function call.
Create at least two cases per category. Use one simple pivot and one pivot after an intermediate function result.
Write expected active state. Do not stop at an expected answer sentence.
Write negative assertions. Specify obsolete values and forbidden functions that must not appear after the pivot.
Run the plain-chat baseline. This establishes behavior for your exact system.
Add a goal summary. Validate its fidelity before it reaches the planner.
Add structured state. Validate schema, revision, permissions, and domain invariants.
Mutation-test the harness. Confirm that intentional defects are detected.
Compare traces. Separate interpretation, memory, planning, and execution failures.
Keep the set as a regression suite. Repeat it after changes to the model, prompt, functions, state schema, or history-compaction logic.
13. Limitations
Synthetic scenarios cover known transitions, not the full variety of natural language. Users may correct a requirement through implication, sarcasm, a reference to an earlier agreement, or several short messages. After the laboratory set is stable, add anonymized patterns from your own product only when their use is permitted.
A fixed catalogue tests state management but does not reproduce network delays, partial failures, concurrent edits, or changing external data. Availability can become stale even when user intent has not changed; test that separately.
Structured state requires a domain model. A schema that is too rigid cannot represent an unexpected related task. A schema that is too loose recreates the ambiguity of free text. Provide a safe needs_clarification state for operations that cannot be mapped confidently.
A summary or state-updater step may add model calls, latency, or orchestration complexity. Compare those costs using telemetry from your own environment. This article intentionally reports no success rates, latency improvements, or cost differences because no common experiment was executed for the reader’s system.
Finally, correct intent recognition does not replace external-action controls. Sending, publishing, purchasing, deleting, or reserving should have explicit permissions, a current-revision check, and human confirmation where the risk requires it.
14. Definition of done
Your evaluation is repeatable when reveal, revision, and function-switch tests demonstrate all of the following:
the latest valid intent is represented as an explicit active version;
results dependent on superseded parameters are invalidated or recomputed;
the obsolete function cannot execute, including from a previously queued action;
permitted function arguments contain the current parameters;
the final response makes no false claim about cancelled or unperformed actions;
a failure can be localized to interpretation, state update, planning, or execution.
Start with the meeting-room fixture, replace rooms with objects from your own process, and preserve the same pivots across all three state variants. The vague question “Did the agent understand the correction?” then becomes a concrete set of checks: which goal became active, which values were superseded, which results were invalidated, and which action actually ran.
Continue with the reproducible methods in Agent Lab Journal guides, and use the Agent Lab Journal glossary for definitions of agent, context, prompts, tool calling, benchmarks, and approval controls.
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