fix(mcp): expose MCP tool input parameters to the agent

MCP server tools were presented to the agent with only their name and a
truncated description: get_tool_descriptions_for_prompt() emitted
"- name: description" and get_all_tools() dropped input_schema entirely.
On the fenced-block tool path (used by Ollama models), the agent could
not see a tool's declared inputs and guessed argument names from the
description alone, so tool calls failed (issue #2509). MCP inspector
showed the schemas fine, confirming the loss was on our side.

- get_all_tools() now carries each tool's input_schema.
- get_tool_descriptions_for_prompt() renders a compact args hint
  (parameter names, coarse types, required-ness) via a new
  _format_mcp_params() helper, matching the "Args (JSON): {...}" style
  the built-in tool descriptions already use.

Fixes #2509

tests/test_mcp_tool_params_in_prompt.py

@@ -0,0 +1,68 @@
+"""Regression for issue #2509 — MCP tools must expose their input parameters.
+
+``McpManager.get_tool_descriptions_for_prompt()`` previously emitted only
+``- name: description`` per MCP tool, so agents (notably on the fenced-block
+tool path used by Ollama models) never saw a tool's declared inputs and guessed
+argument names from the description alone. ``get_all_tools()`` also dropped the
+``input_schema`` entirely. These tests pin that the inputs now reach both
+surfaces.
+"""
+
+from src.mcp_manager import McpManager
+
+
+def _mgr_with_tool() -> McpManager:
+    mgr = McpManager()
+    mgr._tools = {
+        "srv1": [
+            {
+                "name": "fetch_doc",
+                "description": "Fetch a document by path.",
+                "input_schema": {
+                    "type": "object",
+                    "properties": {
+                        "path": {"type": "string", "description": "file path"},
+                        "limit": {"type": "integer"},
+                    },
+                    "required": ["path"],
+                },
+            }
+        ]
+    }
+    mgr._connections = {"srv1": {"status": "connected", "name": "Files", "identity": ""}}
+    return mgr
+
+
+def test_get_all_tools_carries_input_schema():
+    tools = _mgr_with_tool().get_all_tools()
+    assert tools and tools[0]["input_schema"]["properties"]["path"]["type"] == "string"
+
+
+def test_prompt_descriptions_surface_param_names_and_required():
+    text = _mgr_with_tool().get_tool_descriptions_for_prompt()
+    assert "mcp__srv1__fetch_doc" in text
+    assert "path" in text and "limit" in text   # inputs are surfaced to the model
+    assert "required" in text                   # required-ness is surfaced
+
+
+def test_format_mcp_params_handles_no_params():
+    from src.mcp_manager import _format_mcp_params
+
+    assert _format_mcp_params({}) == ""
+    assert _format_mcp_params(None) == ""
+    assert _format_mcp_params({"type": "object", "properties": {}}) == ""
+
+
+def test_format_mcp_params_marks_required_and_types():
+    from src.mcp_manager import _format_mcp_params
+
+    out = _format_mcp_params(
+        {
+            "type": "object",
+            "properties": {"q": {"type": "string"}, "n": {"type": "integer"}},
+            "required": ["q"],
+        }
+    )
+    assert '"q": string (required)' in out
+    assert '"n": integer' in out
+    assert '"n": integer (required)' not in out  # optional param not marked required