Add the gpt6 agent profile kind

lithos ships `metadata.agent.profile = "gpt6"` on the GPT-6 Astra row.
Fabro runs it on the GPT-5.6 harness: the same Codex core tool set,
memory filenames, question tool, and command timeout. The shared
`uses_codex_core_tools` predicate replaces the `== Gpt56` checks so the
two kinds cannot drift apart.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

lib/components/fabro-agent/src/cli.rs

@@ -544,7 +544,7 @@ async fn run_with_args_and_client_and_catalog_styled(
         &model,
         Arc::clone(&catalog),
     );
-    let profile_builder = if profile_kind == AgentProfileKind::Gpt56 {
+    let profile_builder = if profile_kind.uses_codex_core_tools() {
         profile_builder
     } else {
         profile_builder.with_web_fetch_summarizer(Some(build_summarizer(

lib/components/fabro-agent/src/config.rs

@@ -139,9 +139,10 @@ impl NativeToolOptions {
             AgentProfileKind::Kimi => 60_000,
             // Codex's `shell_command` documents a 10s default, which is
             // already fabro's, so GPT-5.6 budgets against the same number.
-            AgentProfileKind::OpenAi | AgentProfileKind::Gemini | AgentProfileKind::Gpt56 => {
-                defaults.default_command_timeout_ms
-            }
+            AgentProfileKind::OpenAi
+            | AgentProfileKind::Gemini
+            | AgentProfileKind::Gpt56
+            | AgentProfileKind::Gpt6 => defaults.default_command_timeout_ms,
         };
         Self {
             default_command_timeout_ms,

lib/components/fabro-agent/src/memory.rs

@@ -34,7 +34,7 @@ pub async fn discover_memory(
         AgentProfileKind::Anthropic | AgentProfileKind::Claude5 => {
             vec!["AGENTS.md", "CLAUDE.md"]
         }
-        AgentProfileKind::OpenAi | AgentProfileKind::Gpt56 => {
+        AgentProfileKind::OpenAi | AgentProfileKind::Gpt56 | AgentProfileKind::Gpt6 => {
             vec!["AGENTS.md", ".codex/instructions.md"]
         }
         AgentProfileKind::Gemini => vec!["AGENTS.md", "GEMINI.md"],

lib/components/fabro-agent/src/profiles/mod.rs

@@ -104,7 +104,7 @@ impl AgentProfileBuilder {
     /// `web_fetch` discard it instead of retaining an unused LLM client.
     #[must_use]
     pub fn with_web_fetch_summarizer(mut self, summarizer: Option<WebFetchSummarizer>) -> Self {
-        if self.profile_kind != AgentProfileKind::Gpt56 {
+        if !self.profile_kind.uses_codex_core_tools() {
             self.summarizer = summarizer;
         }
         self
@@ -115,7 +115,7 @@ impl AgentProfileBuilder {
         let model = self.model.as_str();
         let deps = ProfileDeps {
             options:      self.native_tool_options.clone(),
-            summarizer:   if self.profile_kind == AgentProfileKind::Gpt56 {
+            summarizer:   if self.profile_kind.uses_codex_core_tools() {
                 None
             } else {
                 self.summarizer.clone()
@@ -147,7 +147,7 @@ impl AgentProfileBuilder {
                     .with_provider_id(self.provider_id.clone())
                     .with_catalog(Arc::clone(&self.catalog)),
             ),
-            AgentProfileKind::Gpt56 => Box::new(
+            AgentProfileKind::Gpt56 | AgentProfileKind::Gpt6 => Box::new(
                 Gpt56Profile::with_native_tools(model, &deps)
                     .with_route(self.provider_id.clone(), Arc::clone(&self.catalog)),
             ),

lib/components/fabro-agent/src/question_tools.rs

@@ -194,8 +194,8 @@ pub fn is_question_tool(name: &str) -> bool {
 
 pub fn register_question_tools(profile_kind: AgentProfileKind, registry: &mut ToolRegistry) {
     match profile_kind {
-        // Codex names this tool `request_user_input` for GPT-5.6 too.
-        AgentProfileKind::OpenAi | AgentProfileKind::Gpt56 => {
+        // Codex names this tool `request_user_input` for GPT-5.6 and GPT-6 too.
+        AgentProfileKind::OpenAi | AgentProfileKind::Gpt56 | AgentProfileKind::Gpt6 => {
             registry.register(make_openai_question_tool());
         }
         // Kimi Code names this tool `AskUserQuestion` with the same

lib/foundation/fabro-types/src/agent_profile.rs

@@ -1,8 +1,8 @@
-//! Agent profile vocabulary shared by the catalog policy and the agent.
+//! Agent profile vocabulary shared by the catalog and the agent.
 //!
 //! The catalog records which profile a model should run under in its
-//! `metadata.fabro.agent_profile` entry. This enum is the Rust spelling of
-//! that value.
+//! `metadata.agent.profile` entry, a namespace lithos-llm ships and Pebble
+//! reads too. This enum is the Rust spelling of that value.
 
 use serde::{Deserialize, Serialize};
 use strum::{Display, EnumString, IntoStaticStr, VariantArray};
@@ -47,6 +47,9 @@ pub enum AgentProfileKind {
     /// per provider, so other models on the `openai` provider keep
     /// [`Self::OpenAi`].
     Gpt56,
+    /// GPT-6 models (Astra), which Codex drives with the same narrow tool
+    /// contract as GPT-5.6. Fabro runs them on the GPT-5.6 harness.
+    Gpt6,
 }
 
 impl AgentProfileKind {
@@ -54,6 +57,14 @@ impl AgentProfileKind {
     pub fn as_str(self) -> &'static str {
         self.into()
     }
+
+    /// Whether the profile runs Codex's narrow core tool set (a shell, a file
+    /// editor, and `update_plan`) instead of Fabro's dedicated read,
+    /// discovery, and fetch tools.
+    #[must_use]
+    pub fn uses_codex_core_tools(self) -> bool {
+        matches!(self, Self::Gpt56 | Self::Gpt6)
+    }
 }
 
 #[cfg(test)]
@@ -76,6 +87,9 @@ mod tests {
     fn claude5_and_gpt56_use_their_catalog_spellings() {
         assert_eq!(AgentProfileKind::Claude5.as_str(), "claude-5");
         assert_eq!(AgentProfileKind::Gpt56.as_str(), "gpt56");
+        assert_eq!(AgentProfileKind::Gpt6.as_str(), "gpt6");
+        assert!(AgentProfileKind::Gpt6.uses_codex_core_tools());
+        assert!(!AgentProfileKind::OpenAi.uses_codex_core_tools());
         assert_eq!(AgentProfileKind::OpenAi.as_str(), "openai");
     }
 }