Plugin context from pre_llm_call hooks was injected into the system
prompt, breaking the prompt cache prefix every turn when content
changed (typical for memory plugins). Now all plugin context goes
into the current turn's user message — the system prompt stays
identical across turns, preserving cached tokens.
The system prompt is reserved for Hermes internals. Plugins
contribute context alongside the user's input.
Also adds comprehensive documentation for all 6 plugin hooks:
pre_tool_call, post_tool_call, pre_llm_call, post_llm_call,
on_session_start, on_session_end — each with full callback
signatures, parameter tables, firing conditions, and examples.
Supersedes #5138 which identified the same cache-busting bug
and proposed an uncached system suffix approach. This fix goes
further by removing system prompt injection entirely.
Co-identified-by: OutThisLife (PR #5138)
Major reorganization of the documentation site for better discoverability
and navigation. 94 pages across 8 top-level sections (was 5).
Structural changes:
- Promote Features from 3-level-deep subcategory to top-level section
with new Overview hub page categorizing all 26 feature pages
- Promote Messaging Platforms from User Guide subcategory to top-level
section, add platform comparison matrix (13 platforms x 7 features)
- Create new Integrations section with hub page, grouping MCP, ACP,
API Server, Honcho, Provider Routing, Fallback Providers
- Extract AI provider content (626 lines) from configuration.md into
dedicated integrations/providers.md — configuration.md drops from
1803 to 1178 lines
- Subcategorize Developer Guide into Architecture, Extending, Internals
- Rename "User Guide" to "Using Hermes" for top-level items
Orphan fixes (7 pages now reachable via sidebar):
- build-a-hermes-plugin.md added to Guides
- sms.md added to Messaging Platforms
- context-references.md added to Features > Core
- plugins.md added to Features > Core
- git-worktrees.md added to Using Hermes
- checkpoints-and-rollback.md added to Using Hermes
- checkpoints.md (30-line stub) deleted, superseded by
checkpoints-and-rollback.md (203 lines)
New files:
- integrations/index.md — Integrations hub page
- integrations/providers.md — AI provider setup (extracted)
- user-guide/features/overview.md — Features hub page
Broken link fixes:
- quickstart.md, faq.md: update context-length-detection anchors
- configuration.md: update checkpoints link
- overview.md: fix checkpoint link path
Docusaurus build verified clean (zero broken links/anchors).
The plugin system defined six lifecycle hooks but only pre_tool_call and
post_tool_call were invoked. This activates the remaining four so that
external plugins (e.g. memory systems) can hook into the conversation
loop without touching core code.
Hook semantics:
- on_session_start: fires once when a new session is created
- pre_llm_call: fires once per turn before the tool-calling loop;
plugins can return {"context": "..."} to inject into the ephemeral
system prompt (not cached, not persisted)
- post_llm_call: fires once per turn after the loop completes, with
user_message and assistant_response for sync/storage
- on_session_end: fires at the end of every run_conversation call
invoke_hook() now returns a list of non-None callback return values,
enabling pre_llm_call context injection while remaining backward
compatible (existing hooks that return None are unaffected).
Salvaged from PR #2823.
Co-authored-by: Nicolò Boschi <boschi1997@gmail.com>
