Portable Agent Plugin packages fold the plugin name into the MCP
registry name three times over (slug, digest, and again as the server
key), so mcp__<server>__<tool> routinely exceeds the 64-char function
name limit OpenAI-compatible providers enforce — while the same server
registered via `hermes mcp add` stays well under it. The oversized name
is never rejected loudly; the tool just becomes unreachable. Clamp
mcp_prefixed_tool_name() to 64 chars with a deterministic, collision-
safe hash suffix, mirroring the existing property-key clamp in
schema_sanitizer.py. Dispatch is unaffected since handlers already
close over the original unprefixed tool name.
Fixes#81331
ef0136385c