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Reasoning Coherence assesses whether an agent’s reasoning steps are logically consistent, non-contradictory, and aligned with the intended plan.

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Metric definition

Reasoning Coherence — A binary metric that evaluates internal logical consistency within a single LLM call, with respect to the latest user input.
  • Type: Binary
    • 1 (Coherent): Intermediate reasoning events/summaries are mutually consistent and causally support the LLM input.
    • 0 (Incoherent): Contradictions, conflicting premises, circular logic, or unjustified reversals/jumps exist among the reasoning events.
This metric is primarily used for agentic workflows that involve multi-step planning, tool usage, and intermediate reasoning traces. It helps validate that the steps an agent takes (or proposes) form a coherent path from problem to solution. Here’s a scale that shows the relationship between Reasoning Coherence and potential impact on your AI system:
0100
Low Coherence
Reasoning steps are inconsistent, contradictory, or diverge from the stated plan.
High Coherence
Reasoning is logically consistent and well-aligned to the stated plan and goal.
Scale is 0–100 and is derived from binary judgments converted into a confidence score.

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Calculation method

Reasoning Coherence is computed through a multi-step process:
1

Model Request

One or more evaluation requests are sent to an LLM evaluator to analyze the agent’s reasoning steps and plan alignment.
2

Prompt Engineering

A chain-of-thought style judge prompt guides the evaluator to check for logical consistency, contradictions, and adherence to the plan.
Evaluation rubric (summary): - Intermediate reasoning summaries should support the LLM’s input and each other logically. - No event should invalidate or contradict an earlier inference without explicit, justified retraction. - Explanations and planned actions/tool selections must be mutually reinforcing and consistent with the input. - Web search: The need for a search should be justified by the input/reasoning, and the query/parameters should be appropriate.
3

Multiple Evaluations

The system can request multiple judgments to improve robustness and reduce variance.
4

Result Analysis

Each evaluation produces a binary decision (coherent / not coherent) and an explanation.
5

Result Analysis

Each evaluation produces a binary outcome, where coherent = 1 and not coherent = 0, along with an explanation.
This metric is computed by prompting an LLM and may require multiple LLM calls to compute, which can impact usage and billing.

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Supported nodes

  • LLM span
Inputs considered (when available):
  • Latest user input and current system prompt
  • Intermediate reasoning events and summaries (including plan/steps)
  • Tool-selection thoughts and invoked tool calls (including arguments)
  • Final in-span conclusion/output
Empty or missing reasoning summaries should not be penalized; assess coherence only when there is evidence of incoherence.

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What constitutes coherent reasoning (1)

  • Intermediate reasoning summaries support the LLM’s input and each other logically.
  • No unjustified contradictions: any retractions are explicit and justified.
  • Explanations, planned actions, and tool selections are consistent with the input and mutually reinforcing.
  • Web search is justified by the input/reasoning and uses appropriate parameters (e.g., search query).

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What constitutes incoherent reasoning (0)

  • Explicit contradictions without justification within the reasoning chain.
  • Final (in-span) conclusions or planned actions don’t follow from prior steps.
  • Circular reasoning or unjustified reversals of stance.
  • Tool-selection reasoning conflicts with the recorded input or earlier reasoning steps.
  • The reasoning process deviates from the latest user or system instructions.
  • Web search is unjustified for common-knowledge queries (if unsure, treat as justified), or web search is used when an available specialized tool (e.g., get_weather) is clearly more appropriate for the user’s query.

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Interpreting the score

  • 0–30: Low coherence — reasoning likely contains contradictions or misaligned steps.
  • 31–69: Mixed coherence — review critical steps and provide additional guidance.
  • 70–100: Strong coherence — reasoning appears consistent and aligned.
Consider setting thresholds for alerting or human review based on your domain’s risk tolerance (e.g., flag < 50 for review).

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Example use cases

  • Validating multi-step “plan → execute” agents.
  • Auditing tool-augmented reasoning chains for consistency.
  • Comparing agent versions for planning quality regressions.
  • Example: A financial planning agent develops a step-by-step investment plan, ensuring each recommendation logically follows from prior steps and aligns with the user’s goals.

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Usage

Enable this metric in experiments or Log streams by selecting the Reasoning Coherence scorer. 
from galileo.schema.metrics import GalileoScorers
metric = GalileoScorers.reasoning_coherence

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Best practices

Make plans explicit

Ensure the agent records its plan and intermediate steps so coherence can be evaluated meaningfully.

Refine the rubric

Calibrate the judge rubric with domain examples to reduce false positives/negatives.

Set thresholds

Define minimum acceptable coherence scores and trigger human review below that threshold.

Iterate with CLHF

Use continuous learning via human feedback to improve the judge prompt and rubric over time.