aether_evals/
judge.rs

1use aether_core::events::{AgentEvent, MessageEvent, ToolEvent, TurnEvent, TurnOutcome};
2use futures::StreamExt;
3use llm::{ChatMessage, Context, LlmResponse, StreamingModelProvider};
4use schemars::{JsonSchema, Schema, schema_for};
5use serde::{Deserialize, Serialize};
6use std::borrow::Borrow;
7use std::collections::{BTreeMap, BTreeSet};
8use std::fmt::Write as _;
9use thiserror::Error;
10
11const TRANSCRIPT_PAYLOAD_CHARS: usize = 2_000;
12
13/// Start building an LLM-as-judge from structured context and rubric criteria.
14pub fn judge() -> JudgeBuilder {
15    JudgeBuilder::default()
16}
17
18/// A built judge: the assembled prompt plus the normalized rubric it grades against. Run it with
19/// [`Judge::run`] against a model, or grade a parsed [`JudgeRubricResponse`] with
20/// [`Judge::summarize`].
21#[derive(Debug, Clone)]
22pub struct Judge {
23    pub prompt: String,
24    pub criteria: Vec<JudgeCriterionSpec>,
25}
26
27#[derive(Debug, Clone, Default)]
28pub struct JudgeBuilder {
29    instructions: Option<String>,
30    task: Option<String>,
31    context: JudgeContext,
32    criteria: Vec<JudgeCriterionSpec>,
33}
34
35/// Evidence the judge grades against: the agent transcript, a workspace diff, and/or final files.
36#[derive(Debug, Clone, Default)]
37pub struct JudgeContext {
38    pub transcript: Option<Vec<AgentEvent>>,
39    pub diff: Option<String>,
40    pub files: BTreeMap<String, String>,
41}
42
43/// A single rubric criterion scored on a normalized 0.0..=1.0 scale.
44#[derive(Debug, Clone, JsonSchema)]
45#[serde(rename_all = "camelCase", deny_unknown_fields)]
46pub struct JudgeCriterionSpec {
47    pub id: String,
48    pub description: String,
49    #[serde(default = "default_blocking")]
50    pub blocking: bool,
51    #[serde(default = "default_weight")]
52    pub weight: f64,
53    #[serde(default = "default_threshold")]
54    pub threshold: f64,
55}
56
57/// The graded result of running a judge: an overall pass/score plus per-criterion detail.
58#[derive(Debug, Clone, Serialize, JsonSchema)]
59#[serde(rename_all = "camelCase", deny_unknown_fields)]
60pub struct JudgeSummary {
61    pub passed: bool,
62    pub score: f64,
63    pub reason: String,
64    pub criteria: Vec<JudgeCriterionSummary>,
65}
66
67#[derive(Debug, Clone, Serialize, JsonSchema)]
68#[serde(rename_all = "camelCase", deny_unknown_fields)]
69pub struct JudgeCriterionSummary {
70    pub id: String,
71    pub description: String,
72    pub blocking: bool,
73    pub weight: f64,
74    pub threshold: f64,
75    pub score: f64,
76    pub passed: bool,
77    pub reason: String,
78}
79
80/// The raw rubric response the judge model is expected to return.
81#[derive(Debug, Deserialize, JsonSchema)]
82#[serde(deny_unknown_fields)]
83pub struct JudgeRubricResponse {
84    pub criteria: Vec<JudgeCriterionResponse>,
85    pub overall_reason: String,
86}
87
88#[derive(Debug, Deserialize, JsonSchema)]
89#[serde(deny_unknown_fields)]
90pub struct JudgeCriterionResponse {
91    pub id: String,
92    pub score: f64,
93    pub reason: String,
94}
95
96#[derive(Debug, Error)]
97pub enum JudgeError {
98    #[error("invalid judge input: {0}")]
99    InvalidInput(String),
100
101    #[error("judge LLM stream error: {0}")]
102    Stream(#[from] llm::LlmError),
103
104    #[error("judge returned invalid JSON: {source}\nRaw response: {raw_response}")]
105    InvalidJson {
106        #[source]
107        source: serde_json::Error,
108        raw_response: String,
109    },
110
111    #[error("judge returned invalid judgment: {0}")]
112    InvalidJudgment(String),
113}
114
115impl Judge {
116    pub fn response_schema() -> Schema {
117        JudgeRubricResponse::schema()
118    }
119
120    /// Grade `llm` against this judge's rubric: stream the model's response, parse it as a
121    /// [`JudgeRubricResponse`], and summarize it.
122    pub async fn run(&self, llm: &dyn StreamingModelProvider) -> Result<JudgeSummary, JudgeError> {
123        tracing::info!("Running LLM judge");
124        let raw_response = self.stream_response(llm).await?;
125        let response: JudgeRubricResponse = serde_json::from_str(extract_json_object(&raw_response))
126            .map_err(|source| JudgeError::InvalidJson { source, raw_response: raw_response.clone() })?;
127        self.summarize(response)
128    }
129
130    pub fn summarize(&self, response: JudgeRubricResponse) -> Result<JudgeSummary, JudgeError> {
131        let mut responses = BTreeMap::new();
132        for criterion in response.criteria {
133            let id = criterion.id.clone();
134            if responses.insert(id.clone(), criterion).is_some() {
135                return Err(JudgeError::InvalidJudgment(format!("duplicate response criterion id `{id}`")));
136            }
137        }
138
139        let mut summaries = Vec::with_capacity(self.criteria.len());
140        let mut weighted_score = 0.0;
141        let mut total_weight = 0.0;
142        let mut blocking_failed = false;
143
144        for criterion in &self.criteria {
145            let Some(response) = responses.remove(&criterion.id) else {
146                return Err(JudgeError::InvalidJudgment(format!("missing response criterion `{}`", criterion.id)));
147            };
148            if !response.score.is_finite() || !(0.0..=1.0).contains(&response.score) {
149                return Err(JudgeError::InvalidJudgment(format!(
150                    "criterion `{}` score must be between 0.0 and 1.0",
151                    criterion.id
152                )));
153            }
154
155            let passed = response.score >= criterion.threshold;
156            blocking_failed |= criterion.blocking && !passed;
157            weighted_score += response.score * criterion.weight;
158            total_weight += criterion.weight;
159            summaries.push(JudgeCriterionSummary {
160                id: criterion.id.clone(),
161                description: criterion.description.clone(),
162                blocking: criterion.blocking,
163                weight: criterion.weight,
164                threshold: criterion.threshold,
165                score: response.score,
166                passed,
167                reason: response.reason,
168            });
169        }
170
171        if let Some(id) = responses.keys().next() {
172            return Err(JudgeError::InvalidJudgment(format!("unknown response criterion `{id}`")));
173        }
174
175        let weighted_score = weighted_score / total_weight;
176        let score = if blocking_failed { 0.0 } else { weighted_score };
177        let reason = if blocking_failed {
178            format!("weighted score {:.2}; one or more blockers failed; {}", weighted_score, response.overall_reason)
179        } else {
180            format!("weighted score {:.2}; all blockers met; {}", weighted_score, response.overall_reason)
181        };
182
183        Ok(JudgeSummary { passed: !blocking_failed, score, reason, criteria: summaries })
184    }
185
186    async fn stream_response(&self, llm: &dyn StreamingModelProvider) -> Result<String, JudgeError> {
187        let message = ChatMessage::user(self.prompt.clone());
188        let mut response_stream = llm.stream_response(&Context::new(vec![message], vec![]));
189        let mut raw_response = String::new();
190        while let Some(result) = response_stream.next().await {
191            match result {
192                Ok(LlmResponse::Text { chunk }) => raw_response.push_str(&chunk),
193                Err(error) => return Err(JudgeError::Stream(error)),
194                _ => {}
195            }
196        }
197        Ok(raw_response)
198    }
199}
200
201impl JudgeBuilder {
202    pub fn instructions(mut self, instructions: impl Into<String>) -> Self {
203        self.instructions = Some(instructions.into());
204        self
205    }
206
207    pub fn task(mut self, task: impl Into<String>) -> Self {
208        self.task = Some(task.into());
209        self
210    }
211
212    pub fn transcript(mut self, transcript: impl Into<Vec<AgentEvent>>) -> Self {
213        self.context.transcript = Some(transcript.into());
214        self
215    }
216
217    pub fn diff(mut self, diff: impl Into<String>) -> Self {
218        self.context.diff = Some(diff.into());
219        self
220    }
221
222    pub fn file(mut self, path: impl Into<String>, contents: impl Into<String>) -> Self {
223        self.context.files.insert(path.into(), contents.into());
224        self
225    }
226
227    pub fn files<T, U, V>(mut self, files: T) -> Self
228    where
229        T: IntoIterator<Item = (U, V)>,
230        U: Into<String>,
231        V: Into<String>,
232    {
233        self.context.files.extend(files.into_iter().map(|(path, contents)| (path.into(), contents.into())));
234        self
235    }
236
237    pub fn criteria<T, U>(mut self, criteria: T) -> Self
238    where
239        T: IntoIterator<Item = U>,
240        U: Borrow<JudgeCriterionSpec>,
241    {
242        self.criteria = criteria.into_iter().map(|criterion| criterion.borrow().clone()).collect();
243        self
244    }
245
246    pub fn context(mut self, context: JudgeContext) -> Self {
247        self.context = context;
248        self
249    }
250
251    pub fn build(self) -> Result<Judge, JudgeError> {
252        let task = self.task.ok_or_else(|| JudgeError::InvalidInput("judge task must be provided".to_string()))?;
253        let criteria = normalize_criteria(self.criteria)?;
254        let prompt = build_prompt(&self.instructions.unwrap_or_default(), &task, &self.context, &criteria);
255        Ok(Judge { prompt, criteria })
256    }
257}
258
259impl JudgeCriterionSpec {
260    pub fn new(id: impl Into<String>, description: impl Into<String>) -> Self {
261        Self {
262            id: id.into(),
263            description: description.into(),
264            blocking: default_blocking(),
265            weight: default_weight(),
266            threshold: default_threshold(),
267        }
268    }
269
270    pub fn blocking(mut self, blocking: bool) -> Self {
271        self.blocking = blocking;
272        self
273    }
274
275    pub fn weight(mut self, weight: f64) -> Self {
276        self.weight = weight;
277        self
278    }
279
280    pub fn threshold(mut self, threshold: f64) -> Self {
281        self.threshold = threshold;
282        self
283    }
284}
285
286impl JudgeSummary {
287    /// Failure messages for blocking criteria that scored below their threshold.
288    pub fn blocking_failures(&self) -> impl Iterator<Item = String> + '_ {
289        self.criteria
290            .iter()
291            .filter(|criterion| criterion.blocking && !criterion.passed)
292            .map(|criterion| format!("judge criterion `{}`: {}", criterion.id, criterion.reason))
293    }
294}
295
296impl JudgeRubricResponse {
297    pub fn schema() -> Schema {
298        schema_for!(Self)
299    }
300}
301
302fn build_prompt(instructions: &str, task: &str, context: &JudgeContext, criteria: &[JudgeCriterionSpec]) -> String {
303    let mut sections = vec![
304        format!("## Instructions\n\n{instructions}"),
305        format!("## Task\n\nThe agent you're evaluating was given this task: <task>{task}</task>"),
306    ];
307
308    if let Some(transcript) = &context.transcript
309        && !transcript.is_empty()
310    {
311        sections.push(format!(
312            "## Agent Transcript\n\nTranscript of the agent you're evaluating: <transcript>{}</transcript>",
313            format_transcript(transcript)
314        ));
315    }
316
317    if let Some(diff) = &context.diff
318        && !diff.is_empty()
319    {
320        sections.push(format!("## Git diff\n\nGit diff produced by the agent you're evaluating: <diff>{diff}</diff>"));
321    }
322
323    if !context.files.is_empty() {
324        let blocks = context
325            .files
326            .iter()
327            .map(|(path, contents)| format!("<file><path>{path}</path><contents>{contents}</contents></file>"))
328            .collect::<Vec<_>>()
329            .join("\n");
330        sections.push(format!("## File Contents\n\nFiles under evaluation: <files>{blocks}</files>"));
331    }
332
333    let rubric = criteria
334        .iter()
335        .map(|criterion| {
336            format!(
337                "- id: {}\n  blocking: {}\n  weight: {}\n  threshold: {}\n  description: {}",
338                criterion.id, criterion.blocking, criterion.weight, criterion.threshold, criterion.description
339            )
340        })
341        .collect::<Vec<_>>()
342        .join("\n");
343    sections.push(format!("## Rubric criteria\n\n{rubric}"));
344    sections.push(format!(
345        "{}\n{}\n{}\n{}",
346        "Return exactly one result for every criterion ID above and no extra criteria.",
347        "Scores must be normalized numbers from 0.0 to 1.0.",
348        "Respond with ONLY a JSON object matching this schema:",
349        judge_response_schema()
350    ));
351
352    sections.join("\n\n")
353}
354
355fn normalize_criteria(criteria: Vec<JudgeCriterionSpec>) -> Result<Vec<JudgeCriterionSpec>, JudgeError> {
356    if criteria.is_empty() {
357        return Err(JudgeError::InvalidInput("judge criteria must not be empty".to_string()));
358    }
359
360    let mut ids = BTreeSet::new();
361    let mut normalized = Vec::with_capacity(criteria.len());
362    for mut criterion in criteria {
363        criterion.id = criterion.id.trim().to_string();
364        if criterion.id.is_empty() {
365            return Err(JudgeError::InvalidInput("judge criterion id must not be empty".to_string()));
366        }
367        if !ids.insert(criterion.id.clone()) {
368            return Err(JudgeError::InvalidInput(format!("duplicate judge criterion id `{}`", criterion.id)));
369        }
370        if criterion.description.trim().is_empty() {
371            return Err(JudgeError::InvalidInput(format!(
372                "judge criterion `{}` description must not be empty",
373                criterion.id
374            )));
375        }
376        if !criterion.weight.is_finite() || criterion.weight <= 0.0 {
377            return Err(JudgeError::InvalidInput(format!(
378                "judge criterion `{}` weight must be positive and finite",
379                criterion.id
380            )));
381        }
382        if !criterion.threshold.is_finite() || !(0.0..=1.0).contains(&criterion.threshold) {
383            return Err(JudgeError::InvalidInput(format!(
384                "judge criterion `{}` threshold must be between 0.0 and 1.0",
385                criterion.id
386            )));
387        }
388        normalized.push(criterion);
389    }
390    Ok(normalized)
391}
392
393fn extract_json_object(response: &str) -> &str {
394    let trimmed = response.trim();
395    match (trimmed.find('{'), trimmed.rfind('}')) {
396        (Some(start), Some(end)) if start <= end => &trimmed[start..=end],
397        _ => trimmed,
398    }
399}
400
401fn judge_response_schema() -> String {
402    serde_json::to_string_pretty(&JudgeRubricResponse::schema()).unwrap()
403}
404
405fn default_blocking() -> bool {
406    true
407}
408
409fn default_weight() -> f64 {
410    1.0
411}
412
413fn default_threshold() -> f64 {
414    1.0
415}
416
417fn format_transcript(messages: &[AgentEvent]) -> String {
418    let mut transcript = String::new();
419    for message in messages {
420        if let Some(line) = get_transcript_line(message, TRANSCRIPT_PAYLOAD_CHARS) {
421            let _ = writeln!(transcript, "{line}");
422        }
423    }
424    transcript
425}
426
427fn get_transcript_line(message: &AgentEvent, max_payload_chars: usize) -> Option<String> {
428    match message {
429        AgentEvent::Message(MessageEvent::Text { chunk, is_complete: true, .. }) if !chunk.is_empty() => {
430            Some(format!("[agent] {}", truncate_chars(chunk, max_payload_chars)))
431        }
432        AgentEvent::Tool(ToolEvent::Call { request, .. }) => Some(format!(
433            "[tool-call] {} arguments={}",
434            request.name,
435            truncate_chars(&request.arguments, max_payload_chars)
436        )),
437        AgentEvent::Tool(ToolEvent::Result { result, .. }) => {
438            Some(format!("[tool-result] {}: {}", result.name, truncate_chars(&result.result, max_payload_chars)))
439        }
440        AgentEvent::Tool(ToolEvent::Error { error, .. }) => {
441            Some(format!("[tool-error] {}: {}", error.name, truncate_chars(&error.error, max_payload_chars)))
442        }
443        AgentEvent::Turn(TurnEvent::Ended { outcome: TurnOutcome::Failed { error, .. } }) => {
444            Some(format!("[error] {}", truncate_chars(error, max_payload_chars)))
445        }
446        AgentEvent::Turn(TurnEvent::Ended { outcome: TurnOutcome::Cancelled }) => Some("[cancelled]".to_string()),
447        AgentEvent::Turn(TurnEvent::Ended { outcome: TurnOutcome::Completed }) => Some("[done]".to_string()),
448        _ => None,
449    }
450}
451
452fn truncate_chars(value: &str, max_chars: usize) -> String {
453    if value.chars().count() <= max_chars {
454        return value.to_string();
455    }
456
457    let truncated: String = value.chars().take(max_chars).collect();
458    format!("{truncated}... [truncated]")
459}
460
461#[cfg(test)]
462mod tests {
463    use super::*;
464    use aether_core::events::{AgentEvent, StreamState, TurnOutcome};
465    use llm::testing::FakeLlmProvider;
466    use llm::{LlmError, ProviderError};
467
468    const VALID_RESPONSE: &str = r#"{"criteria":[{"id":"behavior","score":1.0,"reason":"correct"},{"id":"clarity","score":0.5,"reason":"brief"}],"overall_reason":"good"}"#;
469
470    #[test]
471    fn transcript_lines_label_each_message_kind() {
472        let call = AgentEvent::tool_call("call_1", "bash", "{}");
473
474        assert_eq!(
475            get_transcript_line(&AgentEvent::text("msg_1", "hi", StreamState::Complete), 100).unwrap(),
476            "[agent] hi"
477        );
478        assert_eq!(get_transcript_line(&call, 100).unwrap(), "[tool-call] bash arguments={}");
479        assert_eq!(get_transcript_line(&AgentEvent::turn_ended(TurnOutcome::Completed), 100).unwrap(), "[done]");
480    }
481
482    #[test]
483    fn transcript_lines_truncate_long_payloads() {
484        let line = get_transcript_line(&AgentEvent::text("msg_1", &"a".repeat(50), StreamState::Complete), 10).unwrap();
485
486        assert_eq!(line, format!("[agent] {}... [truncated]", "a".repeat(10)));
487    }
488
489    #[test]
490    fn tool_result_transcript_uses_result_arguments() {
491        let message = AgentEvent::tool_result("call_1", "coding__read_file", r#"["Cargo.toml"]"#, "file contents");
492
493        assert_eq!(get_transcript_line(&message, 100).unwrap(), "[tool-result] coding__read_file: file contents");
494    }
495
496    #[test]
497    fn judge_builder_builds_prompt_from_context_and_criteria() {
498        let judge = judge()
499            .instructions("be strict")
500            .task("do the thing")
501            .diff("+added line")
502            .file("notes.txt", "beta\n")
503            .criteria([criterion("works", "the task works", true, 2.0, 0.9)])
504            .build()
505            .unwrap();
506
507        assert!(judge.prompt.contains("## Instructions\n\nbe strict"));
508        assert!(judge.prompt.contains("## Task"));
509        assert!(judge.prompt.contains("The agent you're evaluating was given this task: <task>do the thing</task>"));
510        assert!(judge.prompt.contains("## Git diff"));
511        assert!(judge.prompt.contains("Git diff produced by the agent you're evaluating: <diff>+added line</diff>"));
512        assert!(judge.prompt.contains("## File Contents"));
513        assert!(judge.prompt.contains("<path>notes.txt</path>"));
514        assert!(judge.prompt.contains("<contents>beta\n</contents>"));
515        assert!(judge.prompt.contains("## Rubric criteria"));
516        assert!(judge.prompt.contains("blocking: true"));
517        assert!(judge.prompt.contains("threshold: 0.9"));
518        assert!(judge.prompt.contains("weight: 2"));
519        assert!(judge.prompt.contains("Return exactly one result for every criterion ID above and no extra criteria."));
520        assert!(judge.prompt.contains("Respond with ONLY a JSON object matching this schema:"));
521    }
522
523    #[test]
524    fn judge_builder_renders_transcript_context() {
525        let messages = vec![
526            AgentEvent::tool_call("call_1", "bash", "{}"),
527            AgentEvent::text("msg_1", "all done", StreamState::Complete),
528        ];
529
530        let judge = judge()
531            .task("edit the file")
532            .transcript(messages)
533            .criteria([criterion("behavior", "did it work", true, 1.0, 1.0)])
534            .build()
535            .unwrap();
536
537        assert!(judge.prompt.contains("## Agent Transcript"));
538        assert!(judge.prompt.contains("[tool-call] bash"));
539        assert!(judge.prompt.contains("[agent] all done"));
540    }
541
542    #[test]
543    fn judge_builder_accepts_slice_criteria() {
544        let criteria = vec![criterion("behavior", "does the thing", true, 1.0, 0.8)];
545        let judge = judge().task("do it").criteria(&criteria).build().unwrap();
546        assert_eq!(judge.criteria[0].id, "behavior");
547    }
548
549    #[test]
550    fn judge_summarizes_weighted_rubric() {
551        let judge = judge().task("prompt").criteria(default_criteria()).build().unwrap();
552
553        let summary = judge.summarize(serde_json::from_str(VALID_RESPONSE).unwrap()).unwrap();
554
555        assert!(summary.passed);
556        assert!((summary.score - 0.875).abs() < f64::EPSILON);
557        assert!((summary.criteria[1].score - 0.5).abs() < f64::EPSILON);
558        assert!(summary.reason.contains("all blockers met"));
559    }
560
561    #[test]
562    fn judge_zeroes_score_when_blocker_fails() {
563        let judge = judge().task("prompt").criteria(default_criteria()).build().unwrap();
564        let response = serde_json::from_str(
565            r#"{"criteria":[{"id":"behavior","score":0.75,"reason":"wrong behavior"},{"id":"clarity","score":1.0,"reason":"clear"}],"overall_reason":"bad"}"#,
566        )
567        .unwrap();
568
569        let summary = judge.summarize(response).unwrap();
570
571        assert!(!summary.passed);
572        assert!(summary.score.abs() < f64::EPSILON);
573        assert!(!summary.criteria[0].passed);
574        assert!(summary.reason.contains("one or more blockers failed"));
575    }
576
577    #[test]
578    fn judge_rejects_invalid_criterion_sets() {
579        let judge = judge().task("prompt").criteria(default_criteria()).build().unwrap();
580        for raw_response in [
581            r#"{"criteria":[],"overall_reason":"missing"}"#,
582            r#"{"criteria":[{"id":"behavior","score":1.0,"reason":"ok"},{"id":"behavior","score":1.0,"reason":"ok"}],"overall_reason":"duplicate"}"#,
583            r#"{"criteria":[{"id":"behavior","score":1.0,"reason":"ok"},{"id":"clarity","score":1.0,"reason":"ok"},{"id":"extra","score":1.0,"reason":"ok"}],"overall_reason":"unknown"}"#,
584            r#"{"criteria":[{"id":"behavior","score":1.5,"reason":"bad"},{"id":"clarity","score":1.0,"reason":"ok"}],"overall_reason":"score"}"#,
585        ] {
586            let response = serde_json::from_str(raw_response).unwrap();
587
588            let error = judge.summarize(response).unwrap_err();
589
590            assert!(matches!(error, JudgeError::InvalidJudgment(_)), "response: {raw_response}");
591        }
592    }
593
594    #[test]
595    fn judge_builder_rejects_invalid_inputs() {
596        for (builder, expected) in [
597            (judge().criteria([criterion("behavior", "ok", true, 1.0, 0.8)]), "judge task must be provided"),
598            (judge().task("prompt"), "judge criteria must not be empty"),
599            (
600                judge().task("prompt").criteria([criterion("", "ok", true, 1.0, 0.8)]),
601                "judge criterion id must not be empty",
602            ),
603            (
604                judge().task("prompt").criteria([criterion("behavior", "ok", true, 0.0, 0.8)]),
605                "weight must be positive and finite",
606            ),
607        ] {
608            let error = builder.build().unwrap_err();
609            assert!(error.to_string().contains(expected), "got: {error}");
610        }
611    }
612
613    #[test]
614    fn blocking_failures_report_only_blocking_criteria_below_threshold() {
615        let criterion = |id: &str, blocking, score: f64| JudgeCriterionSummary {
616            id: id.to_string(),
617            description: "desc".to_string(),
618            blocking,
619            weight: 1.0,
620            threshold: 0.8,
621            score,
622            passed: score >= 0.8,
623            reason: format!("{id} reason"),
624        };
625        let summary = JudgeSummary {
626            passed: false,
627            score: 0.0,
628            reason: "r".to_string(),
629            criteria: vec![
630                criterion("met", true, 0.9),
631                criterion("failed", true, 0.5),
632                criterion("advisory", false, 0.0),
633            ],
634        };
635
636        let failures: Vec<String> = summary.blocking_failures().collect();
637
638        assert_eq!(failures, vec!["judge criterion `failed`: failed reason".to_string()]);
639    }
640
641    #[tokio::test]
642    async fn judge_run_extracts_json_object_from_surrounding_prose() {
643        let response = format!("Here is my assessment:\n{VALID_RESPONSE}");
644        let judge_llm = FakeLlmProvider::with_single_response(vec![LlmResponse::text(&response)]);
645        let judge = judge().task("prompt").criteria(default_criteria()).build().unwrap();
646
647        let summary = judge.run(&judge_llm).await.unwrap();
648
649        assert!(summary.passed);
650    }
651
652    #[tokio::test]
653    async fn judge_run_returns_invalid_json_error_with_raw_response() {
654        let judge_llm = FakeLlmProvider::with_single_response(vec![LlmResponse::text("not json")]);
655        let judge = judge().task("prompt").criteria(default_criteria()).build().unwrap();
656
657        let error = judge.run(&judge_llm).await.unwrap_err();
658
659        let JudgeError::InvalidJson { raw_response, .. } = error else {
660            panic!("expected InvalidJson, got {error:?}");
661        };
662        assert_eq!(raw_response, "not json");
663    }
664
665    #[tokio::test]
666    async fn judge_run_returns_stream_error_on_llm_failure() {
667        let judge_llm =
668            FakeLlmProvider::from_results(vec![vec![Err(LlmError::from(ProviderError::api("boom".to_string())))]]);
669        let judge = judge().task("prompt").criteria(default_criteria()).build().unwrap();
670
671        let error = judge.run(&judge_llm).await.unwrap_err();
672
673        assert!(matches!(error, JudgeError::Stream(_)));
674        assert!(error.to_string().contains("boom"));
675    }
676
677    fn criterion(id: &str, description: &str, blocking: bool, weight: f64, threshold: f64) -> JudgeCriterionSpec {
678        JudgeCriterionSpec { id: id.to_string(), description: description.to_string(), blocking, weight, threshold }
679    }
680
681    fn default_criteria() -> Vec<JudgeCriterionSpec> {
682        vec![
683            criterion("behavior", "The behavior is correct.", true, 3.0, 1.0),
684            criterion("clarity", "The response is clear.", false, 1.0, 0.5),
685        ]
686    }
687}
aether_evals/judge.rs

aether_evals/
judge.rs
