feat: Add tool annotations for improved LLM tool understanding

[bryankthompson]

Summary

Adds MCP tool annotations (readOnlyHint, destructiveHint) to all 13 tools to help LLMs better understand tool behavior and make safer decisions about tool execution.

Changes

• Bump MCP SDK from >=1.1.0 to >=1.8.0 for annotation support
• Added readOnlyHint: true to 9 read-only tools (queries, fetches)
• Added destructiveHint: true to 4 tools that create/update/delete data
• Added title annotations for human-readable display

Tool Classification

Read-Only Tools (9):

Tool	Title
obsidian_list_files_in_vault	List Files in Vault
obsidian_list_files_in_dir	List Files in Directory
obsidian_get_file_contents	Get File Contents
obsidian_simple_search	Simple Search
obsidian_complex_search	Complex Search
obsidian_batch_get_file_contents	Batch Get File Contents
obsidian_get_periodic_note	Get Periodic Note
obsidian_get_recent_periodic_notes	Get Recent Periodic Notes
obsidian_get_recent_changes	Get Recent Changes

Destructive Tools (4):

Tool	Title
obsidian_append_content	Append Content
obsidian_patch_content	Patch Content
obsidian_put_content	Put Content
obsidian_delete_file	Delete File

Why This Matters

• Annotations provide semantic metadata that helps LLMs understand tool behavior
• LLMs can make better decisions about when to use tools and in what order
• Enables safer tool execution by distinguishing read-only from destructive operations
• MCP clients (like Claude Code) can auto-approve read-only tools while prompting for destructive ones

Testing

• MCP SDK updated to 1.25.0 (supports annotations)
• uv sync completes successfully
• Pyright type check passes (0 errors)
• Tool annotations verified via Python test script
• All 13 tools have correct readOnlyHint or destructiveHint values

Before/After

Before:

Tool(
    name="obsidian_delete_file",
    description="Delete a file or directory from the vault.",
    inputSchema={...}
)

After:

Tool(
    name="obsidian_delete_file",
    description="Delete a file or directory from the vault.",
    inputSchema={...},
    annotations=ToolAnnotations(
        title="Delete File",
        destructiveHint=True,
    ),
)

🤖 Generated with Claude Code