Glossary¶

Single source of truth for Prism vocabulary. Guides link here on first use of a term; the AI architect cites this file when defining a term.

A¶

AI Architect¶

The Console-hosted chat assistant that answers questions about a connected repository ("how does auth work in this codebase?", "where do I add a new route?"). It is an MCP-tool-using agent that queries the same Prism index coding agents use, then composes grounded answers with citations. Quotas are plan-tiered ("AI Architect units" — see Console AI).

See: Console AI Related: Wiki agent, MCP, Prism Console

AST chunk¶

The unit of code Prism stores and searches over. A tree-sitter parser splits each source file at function/class boundaries, producing chunks that carry symbol_name, signature, and docstring metadata. AST chunks are what the gateway embeds, BM25-indexes, and returns from prism search / prism body / prism def.

See: Indexing Pipeline Related: Code chunk, Description embedding, Four-way RRF

Auto-overlay¶

The CLI behaviour that runs git status and attaches your working-tree dirty files to every read request, so unpushed local edits are reflected in results. It is ON by default for search, find-refs, def, body, outline, module-map, and prepare-edit. Each response reports overlay_files_applied and overlay_consumed so you can tell whether the tool re-parsed the overlay or ran against the indexed snapshot only. Disable with --no-overlay.

See: Branches & Overlays Related: Working-tree dirty files, Branch overlay, indexed_at

B¶

BM25¶

A lexical (keyword-matching) ranking function used as one leg of Prism's hybrid search. Implemented via a PostgreSQL tsvector column on code_chunks, auto-populated by a trigger when chunks are written. BM25 catches exact-token matches (function names, error strings) that pure vector search can rank low.

See: Indexing Pipeline Related: Four-way RRF, AST chunk

Branch overlay¶

A registered record in the branch_overlays table representing a long-lived feature branch. The CLI auto-resolves the nearest overlay via ancestry walk and attaches a diff between HEAD and origin/<overlay-branch> to every read tool's response (_overlay payload). Created with prism branch create <branch>, removed with prism branch delete <branch>. Use for branches expected to live longer than ~1 week — short-lived branches are covered by auto-overlay over dirty files.

See: Branches & Overlays Related: Registered overlay, Auto-overlay, indexed_at

C¶

Code chunk¶

A row in the code_chunks table representing one indexed unit (an AST chunk for source, a ##-delimited section for Markdown). Each row carries the chunk text, a vector embedding, a description embedding (optional), tsvector for BM25, and metadata (file_path, symbol_name, file_role, etc.). All read tools ultimately return references to code chunks.

See: Indexing Pipeline Related: AST chunk, BM25, Description embedding

D¶

Description embedding¶

A second vector embedding per chunk, computed over an LLM-generated one-sentence description of the chunk (instead of the raw code). This lets natural-language queries ("where do we validate JWTs?") match chunks whose code uses different vocabulary than the question. The description vector is the fourth leg fed into four-way RRF.

See: Indexing Pipeline Related: AST chunk, Four-way RRF

F¶

Four-way RRF¶

Reciprocal Rank Fusion over four retrieval legs — vector similarity on the code embedding, BM25, vector similarity on the description embedding, and exact ILIKE match. Each leg is ranked independently, then merged using score = Σ 1 / (k + rank_leg) with k = 60. Chunks ranked by multiple legs win, which is why Prism returns sensible results for both code-shaped and prose-shaped queries.

See: Indexing Pipeline Related: BM25, Description embedding, Code chunk

G¶

Gateway¶

The hosted Prism service that serves MCP tools and REST endpoints over HTTPS. Production URL: https://prism-gateway-xvsemyikqq-oa.a.run.app. It owns auth (JWT RS256), the PostgreSQL + pgvector store, ingestion handlers (Tier 1/2/3), and the search pipeline. Every prism CLI command and chatbot tool call goes through the gateway.

See: Coding Agents Setup, Chatbots Setup Related: MCP, Prism CLI, Streamable-http

I¶

`indexed_at`¶

A timestamp returned with every read-tool response indicating when the underlying index was last refreshed (paired with index_age_seconds). If age exceeds ~3600s and you haven't just connected the repo, the index may be lagging recent collaborator pushes; a refresh hint appears in next_actions. Local edits are covered separately by auto-overlay — indexed_at describes remote staleness, not your working tree.

See: Branches & Overlays Related: Auto-overlay, Branch overlay

Intent tag¶

A lower-snake-case routing handle in a guide's intent_tags frontmatter (e.g. setup_cli, branch_overlay, verify_install). The AI Architect uses these as the primary signal for picking which guide's FAQ to retrieve. The closed vocabulary lives in spec §6.4; adding a new term requires updating §6.4 in the same PR.

See: Console AI Related: AI Architect

M¶

MCP¶

Model Context Protocol — the open spec for connecting LLM clients to external tools and data. Prism is an MCP server: it exposes tools like search_code, get_symbol_definition, find_references, and get_module_map over the protocol. Coding agents typically reach Prism through the prism CLI; chatbots reach it through an MCP transport (direct streamable-http or the mcp-remote bridge).

See: Chatbots Setup Related: Gateway, Streamable-http, MCP-remote bridge

MCP-remote bridge¶

A small Node.js shim, installed via npx -y mcp-remote@latest, that lets an MCP client speak stdio locally while forwarding to a remote streamable-http server with custom headers. Used in the Claude Desktop "Path A" config because Claude Desktop's stdio support is more mature than its direct HTTP MCP support. The canonical snippet is generated by the Console at apps/prism-console/src/pages/settings/tokens/chatbot-prompts.ts.

See: Chatbots Setup Related: MCP, Streamable-http, Gateway

Module map¶

A PageRank-ranked architectural overview of a path, returned by prism module-map <path>. Entries are tiered (core / significant / peripheral) and carry a relative_score from 0 to 1. Call this first when exploring an unfamiliar directory — it gives you the right files to read before issuing targeted searches.

See: CLI Workflow Related: PageRank, Prism CLI

P¶

PageRank¶

The graph algorithm Prism runs over the import graph of an indexed repo, scoring each module by how many other modules import it (weighted by their own importance). PageRank scores are persisted in module_summaries and drive module map tier assignment and several search boosts.

See: Indexing Pipeline Related: Module map

Prism CLI¶

The Python CLI at ~/.local/bin/prism, installed from apps/prism-cli/. The sanctioned interface for coding agents to navigate the codebase — substitutes for Grep/Glob/Read in indexed repos. Reads PRISM_TOKEN and PRISM_BASE_URL from the environment, falling back to ~/.claude.json. Run prism --help to see commands; prism doctor to diagnose a broken install.

See: Coding Agents Setup, CLI Workflow Related: Gateway, Token (developer), Auto-overlay

Prism Console¶

The web UI at the Console URL where tenant admins connect repos, invite teammates, manage developer tokens, and use the AI Architect and Wiki agent. Backed by apps/prism-console-api/ (FastAPI) and apps/prism-console/ (React + Tailwind v4). The Console is the source of truth for chatbot MCP config snippets — guides mirror them.

See: Console Admin Related: AI Architect, Wiki agent, Token (developer)

R¶

Registered overlay¶

A branch overlay that has been created with prism branch create <branch> and exists as a row in branch_overlays. Registration is what unlocks ancestry-walk resolution and _overlay diff attachment on read tools; an unregistered feature branch silently falls back to the default-branch index. Passing --branch <feature> on a read tool returns a branch_unsupported_for_this_tool error only for registered overlays — unregistered branches are ignored.

See: Branches & Overlays Related: Branch overlay, Auto-overlay

Repo connection¶

The act of authorizing Prism to read a GitHub repository, performed in the Console via the GitHub OAuth flow. Creates a repos row, installs a push webhook, and triggers an initial full index. The connected repo's repo_id is what coding-agent tools target via the X-Prism-Repo header or --repo "Owner/Name" flag.

See: Console Admin Related: Prism Console, Tier 3, Gateway

S¶

Streamable-http¶

The MCP transport Prism uses on the /mcp endpoint — stateless request/response over HTTPS, replacing the older SSE-based /sse + /messages pair. Configured in MCP client JSON as "type": "streamable-http" with an Authorization: Bearer <token> header. Eliminates the class of -32602 session errors that plagued the SSE transport. See the Console's generated MCP snippets for the exact JSON shape.

See: Chatbots Setup Related: MCP, Gateway, MCP-remote bridge

T¶

Tier 1¶

File-watcher-driven incremental indexing for the user's own working tree. Triggered locally by an editor or watcher process; pushes individual file deltas to the gateway as you save. Provides the freshest possible index for your machine but does not benefit teammates — see Tier 2 and Tier 3 for shared freshness.

See: Indexing Pipeline Related: Tier 2, Tier 3, Auto-overlay

Tier 2¶

Post-commit-hook indexing. Fires on local git commit, pushing the committed change set to the gateway so the index reflects your commit before you push. Bridges the gap between Tier 1 (per-save) and Tier 3 (per-push).

See: Indexing Pipeline Related: Tier 1, Tier 3

Tier 3¶

GitHub-webhook-driven indexing on the hosted gateway. Fires on every push to the connected repo, runs the incremental indexing pipeline, and updates the shared index that all users of the repo see. This is the primary path for keeping the index fresh across a team.

See: Indexing Pipeline Related: Tier 1, Tier 2, Repo connection

Token (developer)¶

A long-lived bearer token issued by the Console (Settings → Tokens) and used in the Authorization: Bearer <token> header on every gateway call. Tokens never expire and must be treated as secrets — anyone with the token can query every repo the issuing tenant has connected. Rotate via revoke + re-issue; there is no in-place rotation.

See: Coding Agents Setup, Console Admin Related: Prism Console, Gateway, Prism CLI

W¶

Wiki agent¶

The Console feature that synthesizes a structured wiki for a connected repo — overview, architecture, entry points, key components — and persists pages in the wiki_pages table. It runs as a background job after indexing completes (and can be re-run per page). The output is browsed via the Console's Wiki viewer; it does not appear in coding-agent results.

See: Console AI Related: AI Architect, Prism Console

Working-tree dirty files¶

The files git status reports as modified, added, or untracked on your local checkout. The CLI sweeps these per request and attaches them to read calls as the auto-overlay payload, so your unpushed edits are reflected in results. Distinct from a branch overlay, which is a registered server-side construct covering an entire long-lived branch.