Bug Description

When using CLI-based providers (gemini-cli, claude_code, codex, cursor_agent), all new chat sessions are titled ---BEGIN USER MESSAGES--- (or a variation like ---BEGIN USER MESSAGE) instead of a meaningful generated title.

Root Cause

The bug is in the interaction between generate_session_name() in base.rs and generate_simple_session_description() in cli_common.rs.

Step 1 — generate_session_name() (base.rs line ~662) wraps the user messages in markers before calling the LLM:

let user_text = format!(
    "---BEGIN USER MESSAGES---\n{}\n---END USER MESSAGES---\n\nGenerate a short title for the above messages.",
    context.join("\n")
);
let message = Message::user().with_text(&user_text);

Step 2 — CLI providers short-circuit the LLM call via is_session_description_request() (which matches "four words or less" in the system prompt) and dispatch to generate_simple_session_description() instead.

Step 3 — generate_simple_session_description() (cli_common.rs line ~43) naively takes the first 4 words of the first user message:

text.split_whitespace()
    .take(4)
    .collect::<Vec<_>>()
    .join(" ")

Since the first user message is the wrapped prompt ("---BEGIN USER MESSAGES---\n<actual content>..."), the first 4 words are "---BEGIN USER MESSAGES--- <first_real_word>" — producing the broken title.

Affected Providers

All CLI-based providers that use cli_common::generate_simple_session_description:

• gemini_cli.rs (line ~211)
• claude_code.rs (line ~697)
• codex.rs (lines ~683, ~1157, ~1177)
• cursor_agent.rs (line ~337)

Suggested Fix

In cli_common.rs, update generate_simple_session_description to extract the actual user content from within the markers before taking the first 4 words:

.map(|text| {
    // Extract actual content from between the session-naming markers if present
    let actual_text = if let Some(start_idx) = text.find("---BEGIN USER MESSAGES---\n") {
        let after = &text[start_idx + "---BEGIN USER MESSAGES---\n".len()..];
        if let Some(end_idx) = after.find("\n---END USER MESSAGES---") {
            &after[..end_idx]
        } else {
            after
        }
    } else {
        text.as_str()
    };

    actual_text
        .split_whitespace()
        .take(4)
        .collect::<Vec<_>>()
        .join(" ")
})

This fix is isolated to a single function and corrects the behavior for all affected providers simultaneously.

Steps to Reproduce

1. Configure Goose to use any CLI-based provider (gemini-cli, claude_code, codex, or cursor_agent)
2. Start a new chat session
3. Observe that the session title is set to ---BEGIN USER MESSAGES--- instead of a descriptive title