speccoder_runtime/substrate/

near_miss.rs

//! `speccoder.task.near_miss`: wrong and permitted variants of a task's
//! change, to test its acceptance tests.
//!
//! A judge-side call after a task was verified. It sees the task's spec and
//! the final contents of the changed source files — never an acceptance
//! test, visible or held-out, so its variants measure the tests
//! independently. It writes near misses (plausible, and wrong about exactly
//! one stated scenario) and, where the spec leaves a choice open,
//! alternatives the spec permits. It has no tools and no say: code applies
//! each variant, runs the tests and counts. The implementer never sees any
//! of it.

use crate::format::Wording;
use agentplane::prelude::*;
use serde_json::{Value, json};

use super::model_config::{CacheTtl, PromptStyle};

/// The capability the skill provides.
pub const CAPABILITY: &str = "speccoder.task.near_miss";

/// The changed files' contents the author reads, at most.
pub const MAX_SOURCES: usize = 60_000;

/// What the author is told.
pub fn policy(w: &Wording) -> String {
    format!(
        "You help test the acceptance tests of a {product} task. The task's change is final \
and correct by its checks. Write variants of the changed source files, each a complete \
replacement of one or more of those files:\n\
- `wrong`: a plausible implementation a careful developer could believe correct, that \
violates exactly ONE scenario or rule the spec states (an off-by-one at a stated boundary, \
an ignored second example, a missed stated error case). Keep everything else identical; \
it must still build. Never make a variant wrong by breaking behaviour the spec does not \
mention.\n\
- `permitted`: only where the spec leaves a choice open (an order it does not fix, wording \
it does not quote, a tie it does not break), an implementation that makes a different \
allowed choice and still satisfies every stated scenario. If the spec leaves nothing \
open, return no permitted variant.\n\
Name the scenario each variant concerns and say in one line what it gets wrong or which \
freedom it uses. Change only the files you are shown. Answer only in the requested \
structure.",
        product = w.product,
    )
}

/// What the author is told for a bug task's special cases: fixes that
/// recognise a reproduction's literal inputs and keep the old behaviour
/// everywhere else — what a held-out variant with other inputs must catch.
pub fn special_case_policy(w: &Wording) -> String {
    format!(
        "You help test the reproduction tests of a {product} bug fix. The fix is final. For EACH reproduction shown, write one `special_case` variant: a replacement of the changed source files that makes exactly that reproduction pass by recognising its literal inputs (the values, strings or shapes the test uses) and otherwise keeps the code's behaviour from BEFORE the fix. It must build. Name the statement it targets (`E1`, …) as its scenario and say in one line which input it special-cases. Change only the files you are shown. Answer only in the requested structure.",
        product = w.product,
    )
}

/// The special-case author's input: the spec context, the changed files,
/// the change, and the visible reproductions (never a held-out variant).
#[must_use]
pub fn special_case_input(
    bundle: &Value,
    changed: &[(String, String)],
    patch: &str,
    reproductions: &[(String, String, String)],
    context: &speccoder_core::context::ContextManifest,
) -> Tainted<Value> {
    let base = input(bundle, changed, patch, 0, 0);
    let mut v = base.peek().clone();
    v["set"] = json!("special_case");
    v["counts"] = json!({ "special_case": reproductions.len() });
    v["reproductions"] = json!(
        reproductions
            .iter()
            .map(|(statement, path, content)| json!({ "statement": statement, "path": path, "content": content }))
            .collect::<Vec<_>>()
    );
    v["context"] = json!(context);
    Tainted::with_label(v, super::provenance::from(super::provenance::WORKTREE))
}

/// The answer's schema.
#[must_use]
pub fn schema() -> Value {
    schema_of(&["wrong", "permitted"])
}

/// The schema with the kinds `kinds`.
fn schema_of(kinds: &[&str]) -> Value {
    json!({
        "type": "object",
        "properties": {
            "variants": {
                "type": "array",
                "items": {
                    "type": "object",
                    "properties": {
                        "kind": { "type": "string", "enum": kinds },
                        "scenario": { "type": "string" },
                        "rationale": { "type": "string" },
                        "files": {
                            "type": "array",
                            "items": {
                                "type": "object",
                                "properties": {
                                    "path": { "type": "string" },
                                    "content": { "type": "string" },
                                },
                                "required": ["path", "content"],
                                "additionalProperties": false,
                            },
                        },
                    },
                    "required": ["kind", "scenario", "rationale", "files"],
                    "additionalProperties": false,
                },
            },
            "notes": { "type": "array", "items": { "type": "string" } },
        },
        "required": ["variants", "notes"],
        "additionalProperties": false,
    })
}

/// The run input: the task's spec context (the person's), the changed
/// files' final contents and the patch (the worktree's), and how many
/// variants of each kind to write.
#[must_use]
pub fn input(
    bundle: &Value,
    changed: &[(String, String)],
    patch: &str,
    near_miss: u32,
    permitted: u32,
) -> Tainted<Value> {
    let mut budget = MAX_SOURCES;
    let files: Vec<Value> = changed
        .iter()
        .map(|(path, content)| {
            let mut content = content.clone();
            if content.len() > budget {
                let mut end = budget;
                while !content.is_char_boundary(end) {
                    end -= 1;
                }
                content.truncate(end);
            }
            budget = budget.saturating_sub(content.len());
            json!({ "path": path, "content": content })
        })
        .collect();
    let mut patch = patch.to_owned();
    if patch.len() > super::monitor::MAX_PATCH {
        let mut end = super::monitor::MAX_PATCH;
        while !patch.is_char_boundary(end) {
            end -= 1;
        }
        patch.truncate(end);
        patch.push_str("\n… (diff truncated)");
    }
    let worktree = || super::provenance::from(super::provenance::WORKTREE);
    Tainted::object([
        ("story", Tainted::trusted(bundle["story"].clone())),
        ("plan", Tainted::trusted(bundle["plan"].clone())),
        ("task", Tainted::trusted(bundle["task"].clone())),
        (
            "counts",
            Tainted::trusted(json!({ "wrong": near_miss, "permitted": permitted })),
        ),
        ("files", Tainted::with_label(json!(files), worktree())),
        ("patch", Tainted::with_label(json!(patch), worktree())),
    ])
}

fn prompt_raw(input: &Value, ttl: CacheTtl, style: PromptStyle, w: &Wording) -> Value {
    let special = input["set"] == "special_case";
    let system_policy = if special {
        special_case_policy(w)
    } else {
        policy(w)
    };
    let s = |v: &Value| v.as_str().unwrap_or_default().to_owned();
    let files: Vec<String> = input["files"]
        .as_array()
        .into_iter()
        .flatten()
        .map(|f| format!("## {}\n\n```\n{}\n```", s(&f["path"]), s(&f["content"])))
        .collect();
    let parts = [
        format!(
            "# Task {}\n\n{}\n\n# Spec (the task's story)\n\n{}",
            s(&input["task"]["id"]),
            s(&input["task"]["title"]),
            s(&input["story"])
        ),
        format!("# Plan\n\n{}", s(&input["plan"])),
        format!(
            "# The change (git diff)\n\n```diff\n{}\n```\n\n# The changed source files as they are now\n\n{}",
            s(&input["patch"]),
            files.join("\n\n")
        ),
        if special {
            let shown: Vec<String> = input["reproductions"]
                .as_array()
                .into_iter()
                .flatten()
                .map(|r| {
                    format!(
                        "## {} ({})\n\n```\n{}\n```",
                        s(&r["statement"]),
                        s(&r["path"]),
                        s(&r["content"])
                    )
                })
                .collect();
            format!(
                "# The reproductions\n\n{}\n\nWrite one `special_case` variant per reproduction.",
                shown.join("\n\n")
            )
        } else {
            format!(
                "Write {} `wrong` variant(s) and at most {} `permitted` variant(s).",
                input["counts"]["wrong"], input["counts"]["permitted"]
            )
        },
    ];
    match style {
        PromptStyle::OpenAi => json!({
            "system": system_policy,
            "input": [{ "role": "user", "content": parts.iter().map(|t| json!({ "type": "input_text", "text": t })).collect::<Vec<_>>() }],
        }),
        PromptStyle::Anthropic | PromptStyle::Chat => {
            let breakpoint = match ttl {
                CacheTtl::FiveMinutes => json!({ "type": "ephemeral" }),
                CacheTtl::OneHour => json!({ "type": "ephemeral", "ttl": "1h" }),
            };
            json!({
                "system": system_policy,
                "messages": [{ "role": "user", "content": parts.iter().enumerate().map(|(i, t)| {
                    if i == 1 { json!({ "type": "text", "text": t, "cache_control": breakpoint }) }
                    else { json!({ "type": "text", "text": t }) }
                }).collect::<Vec<_>>() }],
            })
        }
    }
}

fn prompt(input: &Value, ttl: CacheTtl, style: PromptStyle, w: &Wording) -> Value {
    let mut out = prompt_raw(input, ttl, style, w);
    if style == PromptStyle::Chat {
        super::model_config::strip_cache_control(&mut out);
    }
    out
}

/// The coded skill.
#[derive(Debug)]
pub struct NearMiss {
    /// Prompt dialect.
    pub style: PromptStyle,
    /// Cache breakpoint lifetime.
    pub cache_ttl: CacheTtl,
    /// The project's spec format.
    pub format: &'static dyn crate::format::Adapter,
}

#[async_trait]
impl Skill for NearMiss {
    fn descriptor(&self) -> SkillDescriptor {
        SkillDescriptor::new("speccoder.task.near_miss").provides(CAPABILITY)
    }

    async fn invoke(
        &self,
        cx: &mut StepCtx<'_>,
        input: Tainted<Value>,
    ) -> Result<Outcome, SkillError> {
        let (ttl, style) = (self.cache_ttl, self.style);
        let prompt = super::provenance::labelled_prompt(
            prompt(input.peek(), ttl, style, self.format.wording()),
            &super::provenance::from(super::provenance::WORKTREE),
        );
        let expecting = if input.peek()["set"] == "special_case" {
            schema_of(&["special_case"])
        } else {
            schema()
        };
        let completion = cx
            .complete_with(&prompt, |call| call.expecting(expecting))
            .await?;
        Ok(Outcome::done(completion.map(|c| {
            json!({
                "answer": c.structured,
                "usage": serde_json::to_value(c.usage).unwrap_or(Value::Null),
            })
        })))
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn the_author_sees_the_spec_and_the_code_never_a_test() {
        let bundle = json!({ "story": "Users log in.", "plan": "p", "task": { "id": "T005", "title": "login" } });
        let input = input(
            &bundle,
            &[("src/lib.rs".to_owned(), "pub fn ok() {}\n".to_owned())],
            "+++ b/src/lib.rs\n",
            2,
            1,
        );
        let v = input.peek();
        assert_eq!(v["counts"], json!({ "wrong": 2, "permitted": 1 }));
        let p = prompt(
            v,
            CacheTtl::FiveMinutes,
            PromptStyle::Anthropic,
            crate::format::at(std::path::Path::new(".")).wording(),
        );
        let text = p.to_string();
        assert!(text.contains("pub fn ok()") && text.contains("Users log in."));
        assert!(!text.contains("acceptance test file"));
        assert_eq!(
            schema()["properties"]["variants"]["items"]["properties"]["kind"]["enum"],
            json!(["wrong", "permitted"])
        );
    }
}