Tool System

TomoriBot exposes built-in BaseTool classes through src/tools/toolRegistry.ts and MCP functions through provider adapters. Centralized availability logic lives in src/tools/availability.ts; it applies provider checks, model capability checks, feature flags, guild MCP collision rules, and deliberate-tool allowlists before tools are sent to the LLM.

Dynamic Tool Assembly

After availability filtering and before provider adapter serialization, built-in tools pass through src/tools/assembly.ts. Most tools are returned unchanged. Capability-sensitive tools can implement assembleForContext(context) to return a per-turn variant with a narrower description, parameters, or enum set, or null to hide the tool when no concrete backend is available.

Current dynamic schema users:

• web_search exposes only categories supported by the active search backend: SearXNG gets all categories, Brave gets text/image/video/news, and DuckDuckGo/Felo MCP fallback gets text-only.
• generate_image exposes only the modes supported by the configured standard image backend: text-to-image, image-to-image/reference fields, and ComfyUI inpaint/outpaint controls are pruned independently. The descriptions of the parameters that survive pruning are also trimmed to the supported modes — prompt only appends inpaint/outpaint guidance when those modes exist, and media_id/denoise only name the reference modes (img2img/inpaint/outpaint) the backend can actually run — so a text-to-image-only backend never sees dead-weight edit-mode instructions. It injects server default positive image tags as prompt guidance, and passes default negative tags only when the custom image endpoint declares workflow_supports.negative_prompt support. ComfyUI image endpoints default that checkbox on; generic custom image endpoints default it off.
• generate_voice_message exposes script markup and optional voice_instructions based on the active speech endpoint and persona voice-design state.

Runtime validation remains required. Assembly prevents the LLM from seeing unsupported options, while execution-time checks still guard stale config, backend health changes, and manually crafted tool calls.

Image generation progress notices are also backend-aware. They only announce default negative tags when a negative-prompt channel is active, always include the image-tags setup hint, list saved user/persona image tags detected in the current context, and call out avatar references separately from message image references.

Persona User Blocking

block_user and unblock_user are built-in Discord tools gated by user_blocking_enabled in /capabilities manage. They write to persona_user_blocks, scoped to the active persona rather than the whole server.

mute blocks only trigger eligibility for that persona. block replaces the target user’s recent live dialogue-history turns and direct media during context building with a single [System: ... sent a message but is currently blocked by you for N more hour(s). Use \unblock_user` to unblock if needed]notice (consecutive messages from the same blocked user collapse into one notice), and suppresses reply annotations that would quote those messages. The notice is an LLM-facing system injection (English, not localized), mirroring reminder/join injections.block` does not remove memories, reminders, documents, short-term memory summaries, or generic references from other users.

Unified Web Tools

web_search is the LLM-visible web search surface. Its dispatcher routes through internal engines and keeps engine-specific tool names hidden. The assembled schema guarantees the category enum for the current turn, so the tool description should not use fail-first language such as “this category may be unavailable” for advertised enum values.

fetch_url is the LLM-visible URL-reading surface. It validates the requested target before dispatch and blocks localhost/private/internal/reserved URLs unless FETCH_URL_ALLOW_PRIVATE_NETWORK=true; the localized failure message names the default FETCH_URL_ALLOW_PRIVATE_NETWORK=false setting so TomoriBot can explain why the fetch failed. Its dispatcher chain is configured by FETCH_URL_ENGINE_ORDER, currently supporting optional crawl4ai followed by mandatory mcp_fetch fallback. Unknown names are ignored, duplicates are collapsed, and mcp_fetch is always appended. Crawl4aiEngine is available only when CRAWL4AI_BASE_URL is set and /health is reachable. McpFetchEngine calls the bundled MCP fetch server internally through FetchHandler.executeFetchInternal(), so the old formatting, pagination, error envelopes, metadata, progress notice, and URL-size validation behavior are preserved while the raw global MCP fetch function is hidden from the LLM.

Guild MCP Replacements

Guild MCP tools are appended after built-in and global MCP filtering, then collision-checked. If a guild enables a url_fetcher MCP server with at least one function, TomoriBot hides bundled fetch_url for that guild so the LLM receives one URL-fetch surface. Prompt macro resolution follows the same rule: {url_fetch_tool} prefers guild url_fetcher functions, then falls back to fetch_url.

NovelAI

fetch_url is not exposed to NovelAI initially. NovelAI GLM tool calling is prompt-based and token-constrained, and fetched-page payloads need separate prompt-budget validation before enabling this tool.