M5c-1 plan: task 08, the turn decision in memoryd

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-09-28 06:57:08 -07:00
parent aef6525cc7
commit 991545c778
3 changed files with 877 additions and 0 deletions
@@ -0,0 +1,155 @@
+//! Where a finished turn goes in Honcho (M5c spec, sections 4 and 5): this agent's trusted or
+//! untrusted workspace, or nowhere, and why. Pure: the session's state as `brokerd` answered it
+//! and the session's log are given, and nothing is read or written here.
+
+use bxcore::sanitize::refuse;
+use bxcore::{DataClass, LogRecord, SessionStateReply};
+
+use crate::honcho::config::is_name;
+use crate::honcho::ledger::{Action, Workspace};
+
+/// Why a turn goes nowhere: the `why` of its `Action::Skip`.
+pub const SECRET_CLASS: &str = "the session is secret";
+pub const NO_SPEAKER: &str = "the turn has no single speaker";
+pub const BAD_SPEAKER: &str = "the speaker is not a Honcho peer name";
+pub const AGENT_SPEAKER: &str = "the speaker has the agent's peer name";
+pub const NO_REPLY: &str = "the turn has no reply";
+pub const SECRET_TEXT: &str = "the turn's text holds a secret";
+
+/// The turn asked for is not in the log.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct NoSuchTurn {
+    pub turn: u64,
+    pub turns: u64,
+}
+
+impl std::fmt::Display for NoSuchTurn {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "turn {} is not in the session's log, which has {} turns",
+            self.turn, self.turns
+        )
+    }
+}
+
+impl std::error::Error for NoSuchTurn {}
+
+/// How many turns the log holds: its `User` records.
+pub fn turns(records: &[LogRecord]) -> u64 {
+    // `records.iter().filter(|r| matches!(r, LogRecord::User { .. })).count()`, as a `u64`:
+    // `u64::try_from(count).unwrap_or(u64::MAX)`.
+    todo!()
+}
+
+/// Where turn `turn` (counted from 1) lies in the log: the index of its `User` record, and the
+/// index just past its last record (the next `User` record's, or the log's length). `None` when
+/// the log has no such turn.
+fn bounds(records: &[LogRecord], turn: u64) -> Option<(usize, usize)> {
+    // `seen: u64 = 0` and `start: Option<usize> = None`. Walk `records.iter().enumerate()`; at
+    // each `LogRecord::User { .. }` (`if let`): if `start` is `Some(start)`, return
+    // `Some((start, index))`; else `seen += 1`, and when `seen == turn`, `start = Some(index)`.
+    // After the loop: `start.map(|start| (start, records.len()))`.
+    todo!()
+}
+
+/// Turn `turn`'s records, from its `User` record to the record before the next `User`.
+pub fn turn_records(records: &[LogRecord], turn: u64) -> Option<&[LogRecord]> {
+    // `let (start, end) = bounds(records, turn)?;` then `records.get(start..end)`.
+    todo!()
+}
+
+/// A Mattermost username as a Honcho peer name: each `.` becomes `_` (M5c spec, section 3).
+pub fn peer_name(speaker: &str) -> String {
+    // `speaker.replace('.', "_")`.
+    todo!()
+}
+
+/// Whether `text` holds a known-prefix secret, by `refuse`'s secret rules alone. `refuse` gives
+/// only the first rule a text breaks, and its character rules come first, so each character they
+/// match is first replaced by a space: it is not a key character and not a letter, so a secret's
+/// prefix and run are found as before, and a carriage return cannot hide a key.
+pub fn has_secret(text: &str) -> bool {
+    // `let mut buf = [0u8; 4];`. `masked: String` is `text.chars().map(..).collect()`, each
+    // char `c` mapped to `' '` when `refuse(c.encode_utf8(&mut buf)).is_some()`, else to `c`.
+    // Then `refuse(&masked).is_some_and(|r| r.rule.starts_with("secret-"))`.
+    todo!()
+}
+
+/// The turn's user text and its speaker, from its first record, the `User` one.
+fn user_text(turn: &[LogRecord]) -> (&str, Option<&str>) {
+    // `match turn.first()`: `Some(LogRecord::User { content, speaker, .. })` ->
+    // `(content.as_str(), speaker.as_deref())`; anything else -> `("", None)`.
+    todo!()
+}
+
+/// The turn's final reply: the content of its last `Assistant` record, when that record asks for
+/// no tool. A turn that stopped in a tool round, or before any answer, has none.
+fn final_reply(turn: &[LogRecord]) -> Option<&str> {
+    // `let last = turn.iter().rev().find(|r| matches!(r, LogRecord::Assistant { .. }));`
+    // then `match last`: `Some(LogRecord::Assistant { content, tool_calls, .. }) if
+    // tool_calls.is_empty()` -> `content.as_deref()`; anything else -> `None`.
+    todo!()
+}
+
+/// Whether any tool result up to the turn's end is labelled untrusted.
+fn labelled_untrusted(records: &[LogRecord]) -> bool {
+    // `records.iter().any(|r| matches!(r, LogRecord::ToolResult { untrusted: true, .. }))`.
+    todo!()
+}
+
+/// Where turn `turn` of the session whose log is `records` goes. `state` is `brokerd`'s answer
+/// for the session; `agent` is `[honcho] agent`. The checks run in this order, and the first that
+/// holds decides: the class `secret`; no speaker; a speaker that is not a peer name, or is the
+/// agent's; no reply; a secret in the user's text or the reply. Otherwise the turn goes to the
+/// untrusted workspace if `brokerd` or any tool result up to the turn's end says untrusted, else
+/// to the trusted one.
+pub fn decide(
+    state: &SessionStateReply,
+    records: &[LogRecord],
+    turn: u64,
+    agent: &str,
+) -> Result<Action, NoSuchTurn> {
+    let missing = NoSuchTurn {
+        turn,
+        turns: turns(records),
+    };
+    let (start, end) = bounds(records, turn).ok_or(missing)?;
+    let upto = records.get(..end).ok_or(missing)?;
+    let this = records.get(start..end).ok_or(missing)?;
+    let skip = |why: &str| {
+        Ok(Action::Skip {
+            why: why.to_string(),
+        })
+    };
+
+    if state.class == DataClass::Secret {
+        return skip(SECRET_CLASS);
+    }
+    let (text, speaker) = user_text(this);
+    let Some(speaker) = speaker else {
+        return skip(NO_SPEAKER);
+    };
+    let peer = peer_name(speaker);
+    if !is_name(&peer) {
+        return skip(BAD_SPEAKER);
+    }
+    if peer == agent {
+        return skip(AGENT_SPEAKER);
+    }
+    let Some(reply) = final_reply(this).filter(|r| !r.trim().is_empty()) else {
+        return skip(NO_REPLY);
+    };
+    if has_secret(text) || has_secret(reply) {
+        return skip(SECRET_TEXT);
+    }
+    let workspace = if state.untrusted || labelled_untrusted(upto) {
+        Workspace::Untrusted
+    } else {
+        Workspace::Trusted
+    };
+    Ok(Action::Turn {
+        workspace,
+        speaker: peer,
+    })
+}