Language-model agents must adapt as users revise their requirements and priorities during complex tasks. We introduce IntentDelta, a human-constructed multi-turn benchmark with 638 trajectories and 3,766 turns across WebShop and TravelPlanner. Each turn pairs a user utterance with a cumulative intention state and human reference actions. The trajectories are cross-verified and cover feasibility- and preference-driven changes in constraints and priorities. We evaluate eleven agents on intention recovery and action quality. Average Intention Recovery is 33.1% in TravelPlanner and 44.7% in WebShop, while average Action Score is 31.6% and 41.0%, respectively. Agents struggle to preserve earlier requirements and distinguish soft preferences from must-have constraints. Correct intention recovery also does not guarantee successful execution, highlighting challenges in translating evolving user intentions into actions.
Figures & tables
Figure 1: Overview of evolving user intentions and agent evaluation. (a) User’s intention: The latent intention, hidden from the agent, evolves in response to real-world observations, including infeasibility and changes in preference. (b) Conversation: The user expresses the revised intention through subsequent utterances. In this example, the user relaxes the budget, demotes the nonstop requirement to a preference, and changes the preferred hotel location. (c) Agent evaluation: The agent is evaluated on both intention understanding and action outcomes.
Benchmark
Data scale
Multi- domain
Construction
Trade-off representation
Change conditions
Human action references
Frames El Asri et al. (2017)
1,369 dialogues
✗
Human
—
Infeasibility
✗
Flex-TravelPlanner Oh et al. (2025)
120 queries + 134 scenarios
✗
Synthetic
Hard/soft
—
NR
COMPASS Qin et al. (2025)
281 tasks
✗
LLM-generated
Hard constraints + utility
—
✗
Evolving User Intent Tack et al. (2026)
450 evaluated source tasks
✓
LLM-generated
—
—
✗
IntentDelta
638 trajectories 3,766 turns
✓
Human
Evolving priorities
Feasibility + preference
✓
Table 1: Benchmark comparison. Multi-domain denotes domain coverage; human action references denote per-turn human reference executions or plans. Dashes indicate no explicit priority/change-condition modeling; NR means not reported. Scale units are retained.
Characteristics
WebShop
TravelPlanner
Change Operations (% of events)
Add
20.4
37.3
Relax
18.0
8.3
Override
15.0
8.5
Reprioritize
46.6
46.0
Change Triggers (% of change turns)
Table 2: Intention change characteristics across WebShop and TravelPlanner. Operation percentages are calculated over change events, while trigger and compound-change percentages are calculated over turns containing intention changes.
Figure 2: Distribution of trajectory lengths across WebShop and TravelPlanner, showing the percentage of trajectories with different numbers of turns.
TravelPlanner
WebShop
Intention
Action
Intention
Action
Model
Det. ↑
Rec. ↑
Hard Succ. ↑
Action Score ↑
Det. ↑
Rec. ↑
Hard Succ. ↑
Action Score ↑
gpt-5.6-sol
70.4
38.4
52.3
49.6
92.2
50.6
58.6
49.0
gpt-5.6-luna
72.1
38.2
46.5
42.3
91.6
49.4
54.6
45.1
claude-opus-4.8
68.4
37.3
47.0
42.3
89.2
52.0
52.0
41.9
claude-sonnet-5
70.8
39.1
55.6
51.6
90.6
50.6
52.0
42.7
Table 3: Main results on TravelPlanner and WebShop. Det. and Rec. denote Detection and Intention Recovery, respectively. All values are on a 0–100 scale; higher is better. Bold indicates the highest numerical value in each column.
Figure 3: Intention recovery of carried-over constraints (not revised in the current turn) by how many turns ago they were introduced. Macro-average over 11 models; the decline holds for all 11 models in both domains.
Figure 4: Priority prediction in (a) TravelPlanner and (b) WebShop. Each row shows the distribution of predicted priorities for a gold priority, normalized to percentages. Diagonal entries indicate correct predictions.
Figure 5: Action Score for turns with fully versus incompletely recovered user intentions in TravelPlanner and WebShop. Full intention recovery is associated with higher Action Scores in both domains.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 6: WebShop annotation interface, illustrated with a ready-to-eat meal task. (a) Annotators edit user utterances, cumulative constraints, and their priorities. (b) Annotators inspect product information, available options, and supporting evidence before selecting a reference product.
Figure 7: TravelPlanner annotation interface. (a) Annotators record a location-specific update allowing up to four billed accommodation nights in Denver while retaining a two-night limit in Colorado Springs, alongside other active constraints and their priorities. (b) Annotators edit a daily reference itinerary and inspect itemized costs and the total trip cost, illustrated with a Cleveland itinerary. The two panels show different trajectories.
Violation category
Full intention recovery
Incomplete recovery
Travel Planner
Budget
79.4%
39.6%
Preferences
10.3%
39.7%
Itinerary structure
3.8%
29.5%
Activity
0.0%
1.3%
Invalid booking (min. stay / capacity)
33.1%
50.4%
Appendix
Table 4: Constraint violations and invalid bookings in action failures, conditioned on intention recovery.
Scoring scheme
TravelPlanner
WebShop
τ / Δrmax
τ / Δrmax
Linear 1:1
1.000 / 0
1.000 / 0
Linear 3:1
1.000 / 0
1.000 / 0
Linear 5:1
0.964 / 1
1.000 / 0
Lexicographic
0.964 / 1
1.000 / 0
Min. tier ratio
0.964 / 1
0.964 / 1
Appendix
Table 5: Sensitivity of model rankings to alternative soft-constraint scoring schemes. Kendall’s τ measures agreement with the original 2:1 ranking; Δrmax denotes the maximum absolute rank change across eleven models.
Domain
Precision ↑
Obsolete retention ↓
TravelPlanner
54.4
14.0
WebShop
84.5
13.8
Appendix
Table 6: Supplementary intention diagnostics (%), averaged across eleven models.