feat(acp): rich content support — images, resources, tool locations

CHANGELOG.md

@@ -60,6 +60,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - Integration tests for ACP transport using `tokio::io::duplex` — `initialize_handshake`, `new_session_and_cancel` (#773)
 - ACP permission persistence to `~/.config/zeph/acp-permissions.toml` — `AllowAlways`/`RejectAlways` decisions survive restarts (#786)
 - `acp.permission_file` config and `ZEPH_ACP_PERMISSION_FILE` env override for custom permission file path (#786)
+- Multi-modal ACP prompts — image and embedded resource content blocks forwarded to LLM providers (#784)
+- Tool output locations for IDE file navigation via `ToolCallLocation` (#784)
 
 ### Fixed
 - Permission cache key collision on anonymous tools — uses `tool_call_id` as fallback when title is absent (#779)

README.md

@@ -65,7 +65,7 @@ zeph --tui         # run with TUI dashboard
 | **Skills-first architecture** | YAML+Markdown skill files with semantic matching, self-learning evolution, 4-tier trust model, and compact prompt mode for small-context models |
 | **Semantic memory** | SQLite + Qdrant (or embedded SQLite vector search) with MMR re-ranking, temporal decay scoring, resilient compaction (reactive retry, middle-out tool response removal, 9-section structured prompt, LLM-free fallback), durable compaction with message visibility control, credential scrubbing, cross-session recall, vector retrieval, autosave assistant responses, and snapshot export/import |
 | **Multi-channel I/O** | CLI, Telegram, Discord, Slack, TUI — all with streaming. Vision and speech-to-text input |
-| **Protocols** | MCP client (stdio + HTTP), A2A agent-to-agent communication, ACP server for IDE integration (multi-session, persistence, idle reaper, permission persistence), sub-agent orchestration |
+| **Protocols** | MCP client (stdio + HTTP), A2A agent-to-agent communication, ACP server for IDE integration (multi-session, persistence, idle reaper, permission persistence, multi-modal prompts with image forwarding), sub-agent orchestration |
 | **Defense-in-depth** | Shell sandbox, tool permissions, secret redaction, SSRF protection, skill trust quarantine, audit logging |
 | **TUI dashboard** | ratatui-based with syntax highlighting, live metrics, file picker, command palette, daemon mode |
 | **Single binary** | ~15 MB, no runtime dependencies, ~50ms startup, ~20 MB idle memory |

crates/zeph-acp/Cargo.toml

@@ -15,6 +15,7 @@ readme = "README.md"
 [dependencies]
 agent-client-protocol.workspace = true
 async-trait.workspace = true
+base64.workspace = true
 dirs.workspace = true
 futures.workspace = true
 schemars.workspace = true

crates/zeph-acp/README.md

@@ -15,7 +15,7 @@ Implements the [Agent Client Protocol](https://agentclientprotocol.org) server s
 
 | Module | Description |
 |--------|-------------|
-| `agent` | `AcpContext` — IDE-proxied capabilities (file executor, shell executor, permission gate, cancel signal) wired into the agent loop per session; `AgentSpawner` factory type; `ZephAcpAgent` ACP protocol handler with multi-session support, LRU eviction, idle reaper, and SQLite persistence |
+| `agent` | `AcpContext` — IDE-proxied capabilities (file executor, shell executor, permission gate, cancel signal) wired into the agent loop per session; `AgentSpawner` factory type; `ZephAcpAgent` ACP protocol handler with multi-session support, LRU eviction, idle reaper, SQLite persistence, and rich content support (images, embedded resources, tool locations) |
 | `transport` | `serve_stdio` / `serve_connection` — ACP server transports; `AcpServerConfig` |
 | `fs` | `AcpFileExecutor` — file system executor backed by IDE-proxied ACP file operations |
 | `terminal` | `AcpShellExecutor` — shell executor backed by IDE-proxied ACP terminal |
@@ -41,6 +41,15 @@ pub struct AcpContext {
 
 The `cancel_signal` is shared with the agent's `LoopbackHandle` so that an IDE cancel request immediately interrupts the running inference loop.
 
+## Rich content
+
+ACP prompts can carry multi-modal content blocks beyond plain text:
+
+- **Images** — base64-encoded image blocks (`image/jpeg`, `image/png`, `image/gif`, `image/webp`) are decoded and forwarded to the LLM provider as inline attachments. Oversized payloads and unsupported MIME types are skipped with a warning.
+- **Embedded resources** — `TextResourceContents` blocks are injected into the prompt text wrapped in `<resource>` markers.
+- **Tool locations** — tool call results can include file path locations (`ToolCallLocation`) that the IDE uses for source navigation.
+- **Thinking chunks** — intermediate reasoning status events are streamed back to the IDE as `session/update` events.
+
 ## Session lifecycle
 
 `ZephAcpAgent` manages multiple concurrent sessions with the following capabilities: