docs: document MCP initialize instructions folding

AGENTS.md

@@ -62,7 +62,7 @@ TOML load/store (`ConfigStore`): `[providers]` tagged union presets, `[database]
 
 `create_client(provider)` maps config `Provider` → protocol client by effective preset (model-level `preset`/`url` overrides apply). `normalize_http_timeout` feeds OpenAI-compatible configs and Anthropic. Mapping: `openai` → `OpenAIClient` (agent uses Responses), `openai-compatible` / `deepseek` → chat-completions clients (deepseek with effective `convention = "responses"` → `DeepseekResponsesClient`, `"anthropic"` → `DeepseekAnthropicClient`), `anthropic` → `AnthropicClient`.
 
-MCP (`runtime/mcp_client.py`): `McpManager` owns one `McpServerConnection` per `[mcp]` server — a spawned stdio subprocess speaking newline-delimited JSON-RPC 2.0: initialize handshake, `tools/list` (cursor pagination), `tools/call`, `notifications/tools/list_changed` → `tools_stale`. Spawn/handshake failures record `connection.error` (status string), never raise; `ensure_started` / `restart(config)` / `aclose` / `refresh_tools`; `statuses()` → `(server, status, tool_count)` rows; per-request timeout from config (default 30s).
+MCP (`runtime/mcp_client.py`): `McpManager` owns one `McpServerConnection` per `[mcp]` server — a spawned stdio subprocess speaking newline-delimited JSON-RPC 2.0: initialize handshake, `tools/list` (cursor pagination), `tools/call`, `notifications/tools/list_changed` → `tools_stale`. Spawn/handshake failures record `connection.error` (status string), never raise; `ensure_started` / `restart(config)` / `aclose` / `refresh_tools`; `statuses()` → `(server, status, tool_count)` rows; `instructions()` → `(server, text)` for every connected server that returned optional `InitializeResult.instructions` (usage guidance captured per connection); per-request timeout from config (default 30s).
 
 ### Memory (`memory/`)
 
@@ -80,7 +80,7 @@ Async SQLAlchemy + aiosqlite. `MemoryStore`: schema init (+ lightweight SQLite `
 - **`/compact`**: soft-compact tool dumps → model summary (no tools) via the same kind dispatch → **new** session seeded with summary message. Soft-compact keeps the last **12** tool results full-size by default (`DEFAULT_RECENT_TOOL_RESULTS`); older tool payloads shrink first.
 - Events: text_delta, **reasoning_delta**, assistant_message, tool_call/result, max_rounds, **error** (`retryable`/`source`), **cancelled** (`reason`), **usage** (`TokenUsage`).
 - Usage: API `usage` from completions (stream with `include_usage`); **char≈token fallback** (~4 chars/token) when omitted; **context size** = last request ``prompt_tokens`` (API preferred); `last_turn_usage` / `session_usage` are **billed sums** (tool rounds re-send history); CLI end-of-turn + `/status`.
-- Config ``[agent]``: `system_prompt` (persona; default `DEFAULT_SYSTEM_PROMPT`; `""` omits persona), `tool_directives` (tool playbook; default `DEFAULT_TOOL_DIRECTIVES`; `""` omits playbook; both empty → no system), `max_tool_result_chars`, `parallel_tools`, `confirm_destructive`, `path_denylist`, `max_context_tokens` (default 200k est. tokens). Truncated tool results carry a model hint (`[Truncated (N chars max; M omitted). You may ask for user to increase the limit via configuration file.]`) so the model can ask the user to raise `max_tool_result_chars`; request-time compact shrinks (`hint=False`) keep the terse `...[truncated N characters]` marker.
+- Config ``[agent]``: `system_prompt` (persona; default `DEFAULT_SYSTEM_PROMPT`; `""` omits persona), `tool_directives` (tool playbook; default `DEFAULT_TOOL_DIRECTIVES`; `""` omits playbook; both empty → no system), `mcp_instructions` (fold connected MCP servers' initialize ``instructions`` into the system prompt when tools on; default true), `max_tool_result_chars`, `parallel_tools`, `confirm_destructive`, `path_denylist`, `max_context_tokens` (default 200k est. tokens). Truncated tool results carry a model hint (`[Truncated (N chars max; M omitted). You may ask for user to increase the limit via configuration file.]`) so the model can ask the user to raise `max_tool_result_chars`; request-time compact shrinks (`hint=False`) keep the terse `...[truncated N characters]` marker.
 
 ### Tools (`tools/`)
 
@@ -108,7 +108,7 @@ Shared interactive I/O: `ask` / `choose` / `form` / `confirm` with pluggable bac
 Click app + readline REPL. Entry: `plyngent` / `python -m plyngent`.
 
 - **`plyngent chat`**: provider/model (flags or interactive; Tab via readline in `prompting`); sessions store `provider_name`/`model` and restore on resume; SQLite via `[database]` (file DB under user data when url unset; explicit `url = ":memory:"` kept + warn); workspace-bound; resume latest for cwd/`--workspace` by default (`--new` / `--session`). One-shot: `-p/--prompt` and non-TTY stdin; exit codes 0/1/2/3; `--yes` (YOLO on), `--stream/--no-stream`, `--quiet`. Root `--log-level`. Enabled `[mcp]` servers start before the REPL (`_start_mcp_manager`, per-server failures warn on stderr) and are closed on exit (`McpManager.aclose`).
-- Slash: Click group in `cli/slash.py` + `awaitlet` for async work; Tab completer from registry + ParamType `shell_complete`. Multiline `"""` … `"""`; `/edit` via `$VISUAL`/`$EDITOR` (blocking only). `/yolo on|off|once` for soft destructive confirms. `/model --persist` / `/models --persist` write model catalog entries into TOML. `/todos` for human show/push/pop/clear of the todo stack. `/mcp` (`list` default) prints per-server status/tool counts + last stderr lines; `/mcp reconnect` re-reads config, restarts every enabled server, and rebuilds the tool registry.
+- Slash: Click group in `cli/slash.py` + `awaitlet` for async work; Tab completer from registry + ParamType `shell_complete`. Multiline `"""` … `"""`; `/edit` via `$VISUAL`/`$EDITOR` (blocking only). `/yolo on|off|once` for soft destructive confirms. `/model --persist` / `/models --persist` write model catalog entries into TOML. `/todos` for human show/push/pop/clear of the todo stack. `/mcp` (`list` default) prints per-server status/tool counts + an `instructions` preview when the server sent usage guidance, + last stderr lines; `/mcp reconnect` re-reads config, restarts every enabled server, and rebuilds the tool registry.
 - `/btw` side questions: forked session; main transcript/DB untouched. `--tools=read` (default) exposes only `READ_ONLY` tools under `read_only_context()` (fetch=GET) with the main session view; `--tools=no` off; `--tools=full` whole-registry clone with fresh session. Tools off: default falls back to no tools; explicit `read`/`full` errors.
 - Explicit `/resume` or `--session` from another workspace prompts: **keep** / **update** / **abort**.
 - Failed/cancelled turns: user kept; **committed tool rounds kept** (side effects not re-run on `/retry`); only unfinished assistant rolled back; Ctrl+C cancels; TTY confirms off-loop; auto-retry 10s/20s/30s then `/retry`.

README.md

@@ -147,6 +147,9 @@ access_key_or_token = "sk-..."
 # tool_directives = '''### Workspace ...'''
 confirm_destructive = true
 max_context_tokens = 200000
+# Fold MCP server initialize ``instructions`` (usage guidance) into the
+# system prompt when tools are on (default true; false ignores server text).
+# mcp_instructions = true
 
 # Optional plugins (entry-point names); default load none. See doc/plugins.md.
 # [plugins]
@@ -157,7 +160,7 @@ Per-provider **`timeout`** is passed to the HTTP session for chat/completions, R
 
 Third-party **plugins**: install a package that declares `project.entry-points."plyngent.tools"` (and later other groups), then allowlist the entry-point name under **`[plugins].enable`**. Details: [doc/plugins.md](doc/plugins.md).
 
-**MCP servers** (Model Context Protocol over stdio): define servers under `[mcp.servers.<name>]` (`command` + `args`, optional `env`/`cwd`/`timeout`/`read_only`) and their tools become agent tools namespaced `mcp__<server>__<tool>` (LOCAL tags; `read_only = true` also marks them READ_ONLY, eligible for `/btw --tools=read`). Names in `[mcp].disable` stay disconnected. In the REPL, `/mcp` lists per-server status and tool counts; `/mcp reconnect` re-reads the config file and restarts every enabled server (adopts newly added ones).
+**MCP servers** (Model Context Protocol over stdio): define servers under `[mcp.servers.<name>]` (`command` + `args`, optional `env`/`cwd`/`timeout`/`read_only`) and their tools become agent tools namespaced `mcp__<server>__<tool>` (LOCAL tags; `read_only = true` also marks them READ_ONLY, eligible for `/btw --tools=read`). Names in `[mcp].disable` stay disconnected. A server may also return optional `instructions` (usage guidance) in its MCP `initialize` response; when tools are on those are folded into the agent system prompt as `MCP server <name> instructions:` blocks (`[agent] mcp_instructions = false` disables), and `/mcp` previews them. In the REPL, `/mcp` lists per-server status and tool counts; `/mcp reconnect` re-reads the config file and restarts every enabled server (adopts newly added ones).
 
 Supported provider presets today:
 

doc/plyngent.example.toml

@@ -29,6 +29,9 @@
 # MCP (Model Context Protocol) servers exposed as agent tools.
 # Defining a server opts it in; tools appear as mcp__<server>__<tool> with
 # LOCAL tags (confirm flow applies). Names in disable stay disconnected.
+# A server's initialize ``instructions`` (usage guidance) is folded into the
+# agent system prompt when tools are on ([agent] mcp_instructions = false
+# disables; /mcp previews what each server sent).
 # [mcp.servers.docs]
 # command = "npx"
 # args = ["-y", "@modelcontextprotocol/server-filesystem", "/tmp"]
@@ -57,6 +60,9 @@ confirm_destructive = true
 path_denylist = ["/secrets/", ".ssh/", ".gnupg/"]
 # Soft context budget in estimated tokens (~4 chars/token when API usage missing).
 max_context_tokens = 200000
+# Fold connected MCP servers' initialize ``instructions`` (usage guidance)
+# into the agent system prompt when tools are on. false = ignore server text.
+# mcp_instructions = true
 # How open-todo nags are injected into model context:
 # developer (default) | user | synthetic_tool | none
 # (legacy system is treated as developer)