crtx-mcp 0.1.2

//! `cortex_memory_accept` MCP tool handler.
//!
//! Promotes a candidate memory to active after verifying the operator's
//! server-side confirmation token (ADR 0047 §3). The old caller-supplied
//! `confirmed: true` pattern (RT1-F4) is replaced with a `confirmation_token`
//! parameter that must match the token generated at server startup — the same
//! mechanism used by `CortexSessionCommitTool`.
//!
//! After token validation the handler composes the full ADR 0026 policy
//! envelope (proof-closure, contradiction, semantic-trust,
//! operator-temporal-use) and delegates to [`cortex_memory::accept`], exactly
//! as `cortex memory accept` does in the CLI.
//!
//! Gates: [`GateId::CommitWrite`].

use std::sync::{Arc, Mutex, RwLock};

use chrono::Utc;
use cortex_core::{
    compose_policy_outcomes, AuditRecordId, MemoryId, PolicyContribution, PolicyOutcome,
};
use cortex_memory::accept as memory_accept;
use cortex_store::{
    repo::{
        memories::{
            accept_open_contradiction_contribution, accept_proof_closure_contribution,
            ACCEPT_OPERATOR_TEMPORAL_USE_RULE_ID, ACCEPT_SEMANTIC_TRUST_RULE_ID,
        },
        ContradictionRepo, MemoryAcceptanceAudit, MemoryRepo,
    },
    verify_memory_proof_closure, Pool,
};
use serde_json::{json, Value};
use tracing::warn;

use crate::tool_handler::{GateId, ToolError, ToolHandler};

/// Stable invariant emitted when `memory_accept` bypasses the ADR 0047 §3
/// token check via auto-commit mode.
pub const MEMORY_ACCEPT_AUTO_COMMIT_INVARIANT: &str = "memory.accept.auto_commit_mode";

/// The `Warn`-floor invariant for the operator temporal-use contributor when
/// no operator attestation is bound on this surface (honest no-attestation
/// floor, not a BreakGlass substitution).
const ACCEPT_OPERATOR_TEMPORAL_AUTHORITY_WARN_NO_ATTESTATION_INVARIANT: &str =
    "memory.accept.operator_temporal_authority.warn_no_attestation";

/// MCP tool: `cortex_memory_accept`.
///
/// Schema:
/// ```text
/// cortex_memory_accept(
///   memory_id:          string,
///   confirmation_token: string,
/// ) ->
///   { accepted: bool, memory_id: string }
/// ```
#[derive(Debug)]
pub struct CortexMemoryAcceptTool {
    pool: Arc<Mutex<Pool>>,
    /// The confirmation token generated at server startup (ADR 0047 §3).
    ///
    /// Shared with `CortexSessionCommitTool` via the same
    /// `Arc<RwLock<Option<String>>>` written once by `serve.rs` before the
    /// stdio loop starts.
    pub session_token: Arc<RwLock<Option<String>>>,
    /// When `true`, the ADR 0047 §3 token check is bypassed.
    ///
    /// Set by `serve.rs` when `CORTEX_MCP_AUTO_COMMIT=1` is present in the
    /// environment. MUST only be used in operator-controlled CI contexts.
    pub auto_commit: bool,
}

impl CortexMemoryAcceptTool {
    /// Construct the tool over a shared, mutex-guarded store connection and
    /// the server-side confirmation token.
    #[must_use]
    pub fn new(
        pool: Arc<Mutex<Pool>>,
        session_token: Arc<RwLock<Option<String>>>,
        auto_commit: bool,
    ) -> Self {
        Self {
            pool,
            session_token,
            auto_commit,
        }
    }
}

impl ToolHandler for CortexMemoryAcceptTool {
    fn name(&self) -> &'static str {
        "cortex_memory_accept"
    }

    fn gate_set(&self) -> &'static [GateId] {
        &[GateId::CommitWrite]
    }

    fn call(&self, params: Value) -> Result<Value, ToolError> {
        // ── 1. Extract memory_id ──────────────────────────────────────────
        let memory_id_str = params["memory_id"]
            .as_str()
            .filter(|s| !s.is_empty())
            .ok_or_else(|| ToolError::InvalidParams("memory_id is required".into()))?;

        // ── 2. Extract confirmation_token ─────────────────────────────────
        let confirmation_token = params
            .get("confirmation_token")
            .and_then(|v| v.as_str())
            .ok_or_else(|| {
                ToolError::InvalidParams(
                    "required parameter `confirmation_token` is missing or not a string".into(),
                )
            })?
            .to_owned();

        // ── 3. Verify the token (or bypass when auto_commit is active) ────
        if self.auto_commit {
            warn!(
                invariant = MEMORY_ACCEPT_AUTO_COMMIT_INVARIANT,
                "cortex_memory_accept: auto-commit mode — token check bypassed \
                 (CORTEX_MCP_AUTO_COMMIT=1) [{}]",
                MEMORY_ACCEPT_AUTO_COMMIT_INVARIANT,
            );
        } else {
            if confirmation_token.is_empty() {
                return Err(ToolError::InvalidParams(
                    "confirmation_token must not be empty".into(),
                ));
            }

            let stored_token = self
                .session_token
                .read()
                .map_err(|_| ToolError::Internal("session token lock poisoned".into()))?
                .clone();

            match stored_token {
                None => {
                    warn!("cortex_memory_accept: session token not initialised — rejecting");
                    return Err(ToolError::Internal(
                        "server session token not initialised".into(),
                    ));
                }
                Some(ref server_token) => {
                    if !tokens_equal(&confirmation_token, server_token) {
                        return Err(ToolError::PolicyRejected(
                            "invalid confirmation token".into(),
                        ));
                    }
                }
            }
        }

        // ── 4. Parse and validate the memory ID ──────────────────────────
        let memory_id: MemoryId = memory_id_str.parse().map_err(|err| {
            ToolError::InvalidParams(format!("memory_id `{memory_id_str}` is invalid: {err}"))
        })?;

        tracing::info!("cortex_memory_accept via MCP: memory_id={}", memory_id);

        // ── 5. Compose the ADR 0026 policy envelope ───────────────────────
        let pool_guard = self
            .pool
            .lock()
            .map_err(|err| ToolError::Internal(format!("pool lock poisoned: {err}")))?;

        let proof_report =
            verify_memory_proof_closure(&pool_guard, &memory_id).map_err(|err| {
                ToolError::Internal(format!(
                    "proof closure preflight failed for {memory_id}: {err}"
                ))
            })?;
        let proof_contribution = accept_proof_closure_contribution(&proof_report);

        let candidate_ref = memory_id.to_string();
        let contradictions = ContradictionRepo::new(&pool_guard)
            .list_open()
            .map_err(|err| {
                ToolError::Internal(format!(
                    "contradiction preflight failed for {memory_id}: {err}"
                ))
            })?;
        let open_contradictions = contradictions
            .iter()
            .filter(|row| row.left_ref == candidate_ref || row.right_ref == candidate_ref)
            .count();
        let contradiction_contribution = accept_open_contradiction_contribution(open_contradictions);

        let semantic_trust_contribution = PolicyContribution::new(
            ACCEPT_SEMANTIC_TRUST_RULE_ID,
            PolicyOutcome::Allow,
            "mcp operator confirmation token validated: \
             candidate passed lineage validation upstream",
        )
        .expect("static semantic trust contribution shape is valid");

        let operator_temporal_use_contribution = PolicyContribution::new(
            ACCEPT_OPERATOR_TEMPORAL_USE_RULE_ID,
            PolicyOutcome::Warn,
            format!(
                "{ACCEPT_OPERATOR_TEMPORAL_AUTHORITY_WARN_NO_ATTESTATION_INVARIANT}: \
                 no operator attestation bound on this MCP surface; accepting at the honest floor",
            ),
        )
        .expect("static operator temporal use contribution shape is valid");

        let policy = compose_policy_outcomes(
            vec![
                proof_contribution,
                contradiction_contribution,
                semantic_trust_contribution,
                operator_temporal_use_contribution,
            ],
            None,
        );

        // ── 6. Execute the accept via the cortex_memory lifecycle layer ───
        let repo = MemoryRepo::new(&pool_guard);
        let audit = MemoryAcceptanceAudit {
            id: AuditRecordId::new(),
            actor_json: json!({"kind": "mcp", "tool": "cortex_memory_accept"}),
            reason: "operator accepted candidate memory via MCP confirmation token".to_string(),
            source_refs_json: json!([memory_id.to_string()]),
            created_at: Utc::now(),
        };

        let accepted_id =
            memory_accept(&repo, &memory_id, Utc::now(), &audit, &policy, &proof_report)
                .map_err(|err| ToolError::PolicyRejected(err.to_string()))?;

        Ok(json!({
            "accepted": true,
            "memory_id": accepted_id.to_string(),
        }))
    }
}

/// Constant-time byte comparison to prevent timing oracle attacks on the
/// confirmation token (ADR 0047 §3).
///
/// Returns `true` only when both strings are identical. The comparison
/// always iterates over every byte of the shorter string even when lengths
/// differ, so it does not short-circuit on length mismatch in a way that
/// leaks information via timing.
fn tokens_equal(a: &str, b: &str) -> bool {
    if a.len() != b.len() {
        return false;
    }
    a.bytes()
        .zip(b.bytes())
        .fold(0u8, |acc, (x, y)| acc | (x ^ y))
        == 0
}

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

    fn make_tool(token: Option<&str>) -> CortexMemoryAcceptTool {
        make_tool_with_auto_commit(token, false)
    }

    fn make_tool_with_auto_commit(
        token: Option<&str>,
        auto_commit: bool,
    ) -> CortexMemoryAcceptTool {
        let pool = Arc::new(Mutex::new(
            cortex_store::Pool::open_in_memory().expect("in-memory sqlite"),
        ));
        let session_token = Arc::new(RwLock::new(token.map(str::to_owned)));
        CortexMemoryAcceptTool::new(pool, session_token, auto_commit)
    }

    /// Missing `confirmation_token` must be rejected with InvalidParams.
    #[test]
    fn missing_confirmation_token_returns_invalid_params() {
        let tool = make_tool(Some("correct-token"));
        let err = tool
            .call(serde_json::json!({"memory_id": "01JSVFAKEAAAAAAAAAAAAAAAAA"}))
            .expect_err("must reject missing token");
        assert!(
            matches!(err, ToolError::InvalidParams(_)),
            "expected InvalidParams, got: {err:?}"
        );
    }

    /// Empty `confirmation_token` must be rejected with InvalidParams.
    #[test]
    fn empty_confirmation_token_returns_invalid_params() {
        let tool = make_tool(Some("correct-token"));
        let err = tool
            .call(serde_json::json!({
                "memory_id": "01JSVFAKEAAAAAAAAAAAAAAAAA",
                "confirmation_token": ""
            }))
            .expect_err("must reject empty token");
        assert!(
            matches!(err, ToolError::InvalidParams(_)),
            "expected InvalidParams, got: {err:?}"
        );
    }

    /// Wrong token must return PolicyRejected.
    #[test]
    fn wrong_token_returns_policy_rejected() {
        let tool = make_tool(Some("correct-token"));
        let err = tool
            .call(serde_json::json!({
                "memory_id": "01JSVFAKEAAAAAAAAAAAAAAAAA",
                "confirmation_token": "wrong-token"
            }))
            .expect_err("must reject wrong token");
        assert!(
            matches!(err, ToolError::PolicyRejected(_)),
            "expected PolicyRejected, got: {err:?}"
        );
        let msg = err.to_string();
        assert!(
            msg.contains("invalid confirmation token"),
            "error must cite ADR 0047 §3 message: {msg}"
        );
    }

    /// Uninitialised server token must fail with Internal, not PolicyRejected.
    #[test]
    fn uninitialised_server_token_returns_internal() {
        let tool = make_tool(None);
        let err = tool
            .call(serde_json::json!({
                "memory_id": "01JSVFAKEAAAAAAAAAAAAAAAAA",
                "confirmation_token": "anything"
            }))
            .expect_err("must fail when server token is uninitialised");
        assert!(
            matches!(err, ToolError::Internal(_)),
            "expected Internal, got: {err:?}"
        );
    }

    /// Missing `memory_id` must be rejected with InvalidParams.
    #[test]
    fn missing_memory_id_returns_invalid_params() {
        let tool = make_tool(Some("tok"));
        let err = tool
            .call(serde_json::json!({"confirmation_token": "tok"}))
            .expect_err("must reject missing memory_id");
        assert!(
            matches!(err, ToolError::InvalidParams(_)),
            "expected InvalidParams, got: {err:?}"
        );
    }

    /// gate_set must declare CommitWrite.
    #[test]
    fn gate_set_declares_commit_write() {
        let tool = make_tool(Some("tok"));
        assert!(
            tool.gate_set().contains(&GateId::CommitWrite),
            "gate_set must include CommitWrite"
        );
    }

    /// gate_set must NOT declare SessionWrite (that was the old, incorrect wiring).
    #[test]
    fn gate_set_does_not_declare_session_write() {
        let tool = make_tool(Some("tok"));
        assert!(
            !tool.gate_set().contains(&GateId::SessionWrite),
            "gate_set must not include SessionWrite"
        );
    }

    /// Tool name matches the MCP schema contract.
    #[test]
    fn tool_name_matches_schema_contract() {
        let tool = make_tool(Some("tok"));
        assert_eq!(tool.name(), "cortex_memory_accept");
    }

    /// In auto-commit mode a missing `confirmation_token` is still InvalidParams.
    #[test]
    fn auto_commit_rejects_missing_token_param() {
        let tool = make_tool_with_auto_commit(Some("server-tok"), true);
        let err = tool
            .call(serde_json::json!({"memory_id": "01JSVFAKEAAAAAAAAAAAAAAAAA"}))
            .expect_err("missing param must still be rejected in auto_commit mode");
        assert!(
            matches!(err, ToolError::InvalidParams(_)),
            "expected InvalidParams, got: {err:?}"
        );
    }

    /// The auto-commit invariant constant has the expected value.
    #[test]
    fn auto_commit_invariant_constant_value() {
        assert_eq!(
            MEMORY_ACCEPT_AUTO_COMMIT_INVARIANT,
            "memory.accept.auto_commit_mode"
        );
    }

    /// Regression guard for RT1-F4: a caller-supplied `confirmed: true` must
    /// NOT bypass the token check.
    ///
    /// Passing `confirmed: true` without a valid `confirmation_token` must
    /// fail with InvalidParams (missing required param), not succeed.
    #[test]
    fn confirmed_bool_true_does_not_bypass_token_check() {
        let tool = make_tool(Some("correct-token"));
        // Pass the old vulnerable parameter — no `confirmation_token`.
        let err = tool
            .call(serde_json::json!({
                "memory_id": "01JSVFAKEAAAAAAAAAAAAAAAAA",
                "confirmed": true
            }))
            .expect_err("confirmed:true without token must be rejected");
        assert!(
            matches!(err, ToolError::InvalidParams(_)),
            "expected InvalidParams (missing confirmation_token), got: {err:?}"
        );
    }
}