Key modules

Symposium is a Rust crate with both a library (src/lib.rs) and a binary (src/bin/cargo-agents.rs). The library re-exports all modules so that integration tests can access internals.

config.rs — application context

Everything hangs off the Symposium struct, which wraps the parsed Config with resolved paths for config, cache, and log directories. Two constructors: from_environment() for production and from_dir() for tests.

Defines the user-wide Config (stored at ~/.symposium/config.toml) with [[agent]] entries, logging, plugin sources, and defaults. Provides plugin_sources() to resolve the effective list of plugin source directories.

agents.rs — agent abstraction

Centralizes agent-specific knowledge: hook registration file paths, skill installation directories, and hook registration logic for each supported agent (Claude Code, GitHub Copilot, Gemini CLI, Codex CLI, Kiro, OpenCode, Goose). Handles the differences between agents — e.g., Claude Code uses .claude/skills/ and Kiro uses .kiro/skills/, while Copilot, Gemini, Codex, OpenCode, and Goose use the vendor-neutral .agents/skills/. OpenCode and Goose are skills-only agents (no hook registration).

init.rs — initialization command

Implements cargo agents init. Prompts for agents (or accepts --add-agent/--remove-agent flags), writes user config, and registers global hooks.

sync.rs — synchronization command

Implements cargo agents sync. Scans workspace dependencies, finds applicable skills from plugin sources, installs them into each configured agent’s skill directory, manages a per-agent .symposium.toml manifest to track installed skills, and cleans up stale skills. Also provides register_hooks() for use by init.

plugins.rs — plugin registry

Scans configured plugin source directories for TOML manifests and parses them into Plugin structs. Each plugin contains SkillGroups (which crates, where to find the skills) and Hooks (event handlers). Also discovers standalone SKILL.md files not wrapped in a plugin. Returns a PluginRegistry — a table of contents that doesn’t load skill content.

skills.rs — skill resolution and matching

Given a PluginRegistry and workspace dependencies, this module resolves skill group sources (fetching from git if needed), discovers SKILL.md files, and evaluates crate predicates at each level (plugin, group, skill) to determine which skills apply.

hook.rs — hook handling

Handles the hook pipeline: parse agent wire-format input → auto-sync → builtin dispatch → plugin hook dispatch → serialize output. When auto-sync is enabled, runs sync as a side effect during hook invocations. Plugin hooks are spawned as shell commands with format routing between agent wire formats and the symposium canonical format.

crate_command.rs — crate source lookup

Contains dispatch_crate(), which resolves a crate’s version and fetches its source code. Called by the CLI’s crate-info command.