@@ -0,0 +1,177 @@
+//! Claude Code as an agent (spec 7.4, 9.2): `claude -p` with `stream-json` in
+//! both directions.
+
+use std::ffi::OsString;
+
+use botloft_core::protocol::AgentKind;
+use bytes::Bytes;
+use serde_json::json;
+
+use super::{Agent, LaunchPlan, Turn};
+
+/// Tools the bot uses without asking: its crew tools (spec 7.4).
+const ALLOWED_TOOLS: &str = "mcp__botloft";
+/// Claude Code's own schedulers: they die with the process and Botloft never
+/// sees them. Work at set times is a routine (spec 7.4, 20).
+const DISALLOWED_TOOLS: &str = "CronCreate,CronDelete,CronList,ScheduleWakeup,RemoteTrigger";
+/// Makes Claude Code load `CLAUDE.md` from `--add-dir` folders (spec 5).
+const ADDITIONAL_MEMORY: &str = "CLAUDE_CODE_ADDITIONAL_DIRECTORIES_CLAUDE_MD";
+/// Where permission requests go (spec 10.1).
+const PERMISSION_TOOL: &str = "mcp__botloft__permission_prompt";
+
+pub struct ClaudeAgent;
+
+impl Agent for ClaudeAgent {
+    fn kind(&self) -> AgentKind {
+        AgentKind::Claude
+    }
+
+    fn args(&self, plan: &LaunchPlan<'_>) -> Vec<OsString> {
+        let mut args: Vec<OsString> = [
+            "-p",
+            "--input-format",
+            "stream-json",
+            "--output-format",
+            "stream-json",
+            "--verbose",
+            "--include-partial-messages",
+            "--replay-user-messages",
+        ]
+        .into_iter()
+        .map(OsString::from)
+        .collect();
+        args.push(
+            if plan.resumed {
+                "--resume"
+            } else {
+                "--session-id"
+            }
+            .into(),
+        );
+        args.push(plan.session.into());
+        for arg in [
+            "--setting-sources",
+            "project,local",
+            "--strict-mcp-config",
+            "--permission-mode",
+            plan.permission_mode.cli_value(),
+            "--permission-prompt-tool",
+            PERMISSION_TOOL,
+            "--allowedTools",
+            ALLOWED_TOOLS,
+            "--disallowedTools",
+            DISALLOWED_TOOLS,
+            "--mcp-config",
+        ] {
+            args.push(arg.into());
+        }
+        args.push(plan.mcp_config.as_os_str().to_owned());
+        args.push("--add-dir".into());
+        args.push(plan.work_folder.as_os_str().to_owned());
+        // Without the flag, Claude Code uses the default of the owner's plan.
+        if let Some(model) = plan.model.cli_value() {
+            args.push("--model".into());
+            args.push(model.into());
+        }
+        // Without the flag, Claude Code uses the level it sets for the model.
+        if let Some(effort) = plan.effort.cli_value() {
+            args.push("--effort".into());
+            args.push(effort.into());
+        }
+        args
+    }
+
+    fn extra_env(&self) -> Vec<(OsString, OsString)> {
+        // Loads the work folder's CLAUDE.md with the bot's memory.
+        vec![(OsString::from(ADDITIONAL_MEMORY), OsString::from("1"))]
+    }
+
+    fn encode_turn(&self, uuid: &str, turn: &Turn) -> Bytes {
+        let mut content = vec![json!({ "type": "text", "text": turn.text })];
+        content.extend(turn.images.iter().map(|image| {
+            json!({
+                "type": "image",
+                "source": {
+                    "type": "base64",
+                    "media_type": image.media_type,
+                    "data": image.data,
+                },
+            })
+        }));
+        let event = json!({
+            "type": "user",
+            "uuid": uuid,
+            "message": { "role": "user", "content": content },
+        });
+        let mut line = event.to_string().into_bytes();
+        line.push(b'\n');
+        Bytes::from(line)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use botloft_core::protocol::{BotEffort, BotModel, PermissionMode};
+
+    use super::*;
+    use crate::agent::TurnImage;
+
+    fn plan(resumed: bool, model: BotModel, effort: BotEffort) -> LaunchPlan<'static> {
+        LaunchPlan {
+            session: "abc",
+            resumed,
+            mcp_config: Path::new("w/.botloft/mcp.json"),
+            work_folder: Path::new("w/shared"),
+            permission_mode: PermissionMode::Default,
+            model,
+            effort,
+        }
+    }
+
+    fn strings(args: Vec<OsString>) -> Vec<String> {
+        args.into_iter()
+            .map(|arg| arg.to_string_lossy().into_owned())
+            .collect()
+    }
+
+    #[test]
+    fn a_new_bot_gets_a_session_id_and_the_defaults_leave_model_and_effort_out() {
+        let args = strings(ClaudeAgent.args(&plan(false, BotModel::Default, BotEffort::Default)));
+        let at = args.iter().position(|a| a == "--session-id").expect("flag");
+        assert_eq!(args[at + 1], "abc");
+        assert!(!args.contains(&"--resume".to_owned()));
+        assert!(!args.contains(&"--model".to_owned()));
+        assert!(!args.contains(&"--effort".to_owned()));
+        assert!(args.contains(&"--permission-prompt-tool".to_owned()));
+    }
+
+    #[test]
+    fn a_resumed_bot_with_a_model_and_effort_passes_them() {
+        let args = strings(ClaudeAgent.args(&plan(true, BotModel::Sonnet, BotEffort::High)));
+        assert!(args.contains(&"--resume".to_owned()));
+        let at = args.iter().position(|a| a == "--model").expect("model");
+        assert_eq!(args[at + 1], "sonnet");
+        let at = args.iter().position(|a| a == "--effort").expect("effort");
+        assert_eq!(args[at + 1], "high");
+    }
+
+    #[test]
+    fn a_turn_is_one_user_line_with_its_images() {
+        let turn = Turn {
+            text: "hi".into(),
+            images: vec![TurnImage {
+                media_type: "image/png".into(),
+                data: "AAAA".into(),
+            }],
+        };
+        let line = ClaudeAgent.encode_turn("u-1", &turn);
+        assert!(line.ends_with(b"\n"));
+        let json: serde_json::Value = serde_json::from_slice(&line).expect("json");
+        assert_eq!(json["type"], "user");
+        assert_eq!(json["uuid"], "u-1");
+        assert_eq!(json["message"]["content"][0]["text"], "hi");
+        assert_eq!(json["message"]["content"][1]["source"]["data"], "AAAA");
+    }
+}
@@ -0,0 +1,69 @@
+//! The agent behind a bot (spec 30): Claude Code today, Codex and Antigravity
+//! later. What is specific to one agent lives behind [`Agent`]; the rest of the
+//! daemon asks it and never writes an agent's command line or stdin framing
+//! itself. This first slice owns the process arguments and the encoding of a
+//! turn; reading the output and the approvals follow (spec 30.1, A1).
+
+mod claude;
+
+use std::ffi::OsString;
+use std::path::Path;
+
+use botloft_core::protocol::{AgentKind, BotEffort, BotModel, PermissionMode};
+use bytes::Bytes;
+
+pub use claude::ClaudeAgent;
+
+/// One image that goes in the turn, already read and encoded.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct TurnImage {
+    pub media_type: String,
+    /// The file's bytes, base64.
+    pub data: String,
+}
+
+/// What a bot is told in one turn, whatever the agent.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Turn {
+    pub text: String,
+    pub images: Vec<TurnImage>,
+}
+
+/// What an agent needs to build the command line of a bot's process.
+pub struct LaunchPlan<'a> {
+    /// The conversation: resumed when `resumed`, new with this id otherwise.
+    pub session: &'a str,
+    pub resumed: bool,
+    /// The bot's MCP configuration (the Botloft server and the owner's).
+    pub mcp_config: &'a Path,
+    /// The crew's work folder, which the bot edits like its own (spec 5).
+    pub work_folder: &'a Path,
+    pub permission_mode: PermissionMode,
+    pub model: BotModel,
+    pub effort: BotEffort,
+}
+
+pub trait Agent: Send + Sync + 'static {
+    fn kind(&self) -> AgentKind;
+
+    /// The arguments of the process, after the program.
+    fn args(&self, plan: &LaunchPlan<'_>) -> Vec<OsString>;
+
+    /// Variables the agent needs beyond the ones every bot gets.
+    fn extra_env(&self) -> Vec<(OsString, OsString)>;
+
+    /// One turn as the bytes written to the process's stdin; `uuid` is what
+    /// the agent gives back when the turn begins.
+    fn encode_turn(&self, uuid: &str, turn: &Turn) -> Bytes;
+}
+
+static CLAUDE: ClaudeAgent = ClaudeAgent;
+
+/// The agent that runs bots of `kind`; `None` while the daemon cannot run
+/// that agent yet (spec 30.1).
+pub fn of(kind: AgentKind) -> Option<&'static dyn Agent> {
+    match kind {
+        AgentKind::Claude => Some(&CLAUDE),
+        AgentKind::Codex | AgentKind::Agy => None,
+    }
+}
@@ -12,14 +12,15 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use botloft_core::ids::BotId;
-use botloft_core::protocol::{BotState, Delivery, Message, SenderKind, Task};
+use botloft_core::protocol::{AgentKind, BotState, Delivery, Message, SenderKind, Task};
 use botloft_store::{DeliveryOutcome, Store, StoreError};
 use tokio::sync::Notify;
 use tracing::{debug, warn};
 
 use self::render::{Context, Rendered, render};
 pub use self::settings::CourierSettings;
 use self::sleep::{became_ready, hasten, next_wait};
+use crate::agent::{self, ClaudeAgent};
 use crate::clock;
 use crate::service::tasks;
 use crate::state::{Daemon, Event};
@@ -228,6 +229,7 @@ fn prepare(daemon: &Daemon, store: &Store, delivery: &Delivery) -> Result<Step,
         .map(|(reaction, quote)| (reaction.emoji, quote))
         .collect();
     Ok(Step::Send(Box::new(Draft {
+        agent: bot.agent,
         workspace: daemon.paths.bot_workspace(&crew.slug, &bot.slug),
         message,
         crew_name: crew.name,
@@ -242,6 +244,7 @@ fn prepare(daemon: &Daemon, store: &Store, delivery: &Delivery) -> Result<Step,
 
 /// A delivery about to go, read from the store.
 struct Draft {
+    agent: AgentKind,
     message: Message,
     crew_name: String,
     sender_handle: Option<String>,
@@ -271,7 +274,9 @@ impl Draft {
                 .map(|(id, text)| (id.as_str(), text.as_str())),
             reactions: &self.reactions,
         };
-        render(&self.message, &context, now)
+        // Only agents the daemon runs get this far; the bot was checked at launch.
+        let agent = agent::of(self.agent).unwrap_or(&ClaudeAgent);
+        render(&self.message, &context, now, agent)
     }
 }