docs: added docs for the new and improved sisyhpus agent system

Agents.md

@@ -736,14 +736,20 @@ available; only the auto-injected prompt text is suppressed.
 Coyote comes packaged with some useful built-in agents:
 
 * `coder`: An agent to assist you with all your coding tasks
-* `code-reviewer`: A [CodeRabbit](https://coderabbit.ai)-style code reviewer that spawns per-file reviewers using the teammate messaging pattern
+* `code-reviewer`: A [CodeRabbit](https://coderabbit.ai)-style code reviewer that spawns per-file reviewers using the 
+   teammate messaging pattern
 * `demo`: An example agent to use for reference when learning to create your own agents
 * `deep-research`: A graph-based agent designed to perform deep web research 
 * `explore`: An agent designed to help you explore and understand your codebase
 * `file-reviewer`: An agent designed to perform code-review on a single file (used by the `code-reviewer` agent)
+* `librarian`: A graph-based agent that researches external references. It finds official docs, production OSS examples, 
+   and web best practices. The "external grep" sibling of `explore` (which handles internal/codebase grep). Designed to 
+   be delegated to by `sisyphus` whenever an unfamiliar library, API, or framework is involved.
 * `oracle`: An agent for high-level architecture, design decisions, and complex debugging
 * `report-writer`: An agent to polish research findings into clear, citation-preserving final reports
-* `sisyphus`: A powerhouse orchestrator agent for writing complex code and acting as a natural language interface for your codebase (similar to ClaudeCode, Gemini CLI, Codex, or OpenCode). Uses sub-agent spawning to delegate to `explore`, `coder`, and `oracle`.
+* `sisyphus`: A powerhouse orchestrator agent for writing complex code and acting as a natural language interface for 
+   your codebase (similar to ClaudeCode, Gemini CLI, Codex, or OpenCode). Uses sub-agent spawning to delegate to 
+   `explore`, `librarian`, `coder`, and `oracle`.
 * `sql`: A universal SQL agent that enables you to talk to any relational database in natural language
 
 Coyote writes these built-in agents to your agents directory on first run and never overwrites them afterward, so any

Graph-Agents.md

@@ -1516,6 +1516,11 @@ A short, honest list of things that bite people:
 - [`graph.example.yaml`](https://github.com/Dark-Alex-17/coyote/blob/main/graph.example.yaml) - A fully-commented, full-featured reference
   graph agent at the root of the Coyote repository (every top-level field,
   every node type).
+- Built-in graph agents shipped with Coyote:
+  [`coder`](https://github.com/Dark-Alex-17/coyote/blob/main/assets/agents/coder) (implement -> verify_build -> verify_tests -> self_review -> fix-loop),
+  [`deep-research`](https://github.com/Dark-Alex-17/coyote/blob/main/assets/agents/deep-research) (the canonical reference that exercises every node type),
+  [`librarian`](https://github.com/Dark-Alex-17/coyote/blob/main/assets/agents/librarian) (triage -> parallel doc + OSS search -> synthesize -> trim; a compact illustration of static fan-out with reducers).
+  See [Agents > Built-In Agents](Agents#built-in-agents) for descriptions.
 - [Agents](Agents) - non-graph agent system (config.yaml + LLM loop)
 - [Custom Tools](Custom-Tools) - building `tools.sh` / `tools.py` /
   `tools.ts` files for use in graph nodes