QMD Query Syntax

QMD queries are structured documents with typed sub-queries. Each line specifies a search type and query text.

Grammar

query          = expand_query | query_document ;
expand_query   = text | explicit_expand ;
explicit_expand= "expand:" text ;
query_document = { typed_line } ;
typed_line     = type ":" text newline ;
type           = "lex" | "vec" | "hyde" ;
text           = quoted_phrase | plain_text ;
quoted_phrase  = '"' { character } '"' ;
plain_text     = { character } ;
newline        = "\n" ;

Query Types

Type	Method	Description
`lex`	BM25	Keyword search with exact matching
`vec`	Vector	Semantic similarity search
`hyde`	Vector	Hypothetical document embedding

Default Behavior

A QMD query is either a single expand query or a multi-line query document. Any single-line query with no prefix is treated as an expand query and passed to the expansion model, which emits lex, vec, and hyde variants automatically.

# These are equivalent and cannot be combined with typed lines:
how does authentication work
expand: how does authentication work

Lex Query Syntax

Lex queries support special syntax for precise keyword matching:

lex_query   = { lex_term } ;
lex_term    = negation | phrase | word ;
negation    = "-" ( phrase | word ) ;
phrase      = '"' { character } '"' ;
word        = { letter | digit | "'" } ;

Syntax	Meaning	Example
`word`	Prefix match	`perf` matches "performance"
`"phrase"`	Exact phrase	`"rate limiter"`
`-word`	Exclude term	`-sports`
`-"phrase"`	Exclude phrase	`-"test data"`

Examples

lex: CAP theorem consistency
lex: "machine learning" -"deep learning"
lex: auth -oauth -saml

Vec Query Syntax

Vec queries are natural language questions. No special syntax — just write what you're looking for.

vec: how does the rate limiter handle burst traffic
vec: what is the tradeoff between consistency and availability

Hyde Query Syntax

Hyde queries are hypothetical answer passages (50-100 words). Write what you expect the answer to look like.

hyde: The rate limiter uses a sliding window algorithm with a 60-second window. When a client exceeds 100 requests per minute, subsequent requests return 429 Too Many Requests.

Multi-Line Queries

Combine multiple query types for best results. First query gets 2x weight in fusion.

lex: rate limiter algorithm
vec: how does rate limiting work in the API
hyde: The API implements rate limiting using a token bucket algorithm...

Expand Queries

An expand query stands alone; it's not mixed with typed lines. You can either rely on the default untyped form or add the explicit expand: prefix:

expand: error handling best practices
# equivalent
error handling best practices

Both forms call the local query expansion model, which generates lex, vec, and hyde variations automatically.

Constraints

Top-level query must be either a standalone expand query or a multi-line document
Query documents allow only lex, vec, and hyde typed lines (no expand: inside)
lex syntax (-term, "phrase") only works in lex queries
Empty lines are ignored
Leading/trailing whitespace is trimmed

MCP/HTTP API

The query tool accepts a query document:

{
  "q": "lex: CAP theorem\nvec: consistency vs availability",
  "collections": ["docs"],
  "limit": 10
}

Or structured format:

{
  "searches": [
    { "type": "lex", "query": "CAP theorem" },
    { "type": "vec", "query": "consistency vs availability" }
  ]
}

CLI

# Single line (implicit expand)
qmd query "how does auth work"

# Multi-line with types
qmd query $'lex: auth token\nvec: how does authentication work'

# Structured
qmd query $'lex: keywords\nvec: question\nhyde: hypothetical answer...'

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