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Glama

lancedb_query

Retrieve ranked context chunks from a local LanceDB table to answer user questions with RAG; supports table selection, result limits, and context budgets.

Instructions

RAG query with context retrieval from LanceDB

Input Schema

NameRequiredDescriptionDefault
limitNoMaximum number of chunks to retrieve (default: the configured limit, 20; at most 200)
tableNoTable to query (default: the configured table)
questionYesThe user's question
warmStartNoRetrieve a general project overview instead of answering the question
contextBudgetNoMaximum characters of context to return (default: the configured budget, 8000)

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.2.0

TDQS

C2.6/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full behavioral burden and discloses almost nothing: it does not state that the operation is read-only, whether the question is embedded and searched, what the returned context looks like, or how warmStart changes behavior. Only the words 'context retrieval' hint at the return shape.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence with no wasted words, satisfying conciseness. Its brevity, however, borders on under-specification rather than purposeful economy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a five-parameter RAG tool with no annotations and no output schema, the description is far too thin. It does not explain the relationship between the question and returned chunks, what warmStart produces, or how contextBudget interacts with limit, leaving the agent to reconstruct behavior from parameter names alone.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all five parameters (question, table, limit, contextBudget, warmStart) are already documented in the schema. The description adds no parameter-level meaning beyond what the schema provides, making the baseline 3 appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose3/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a resource (LanceDB) and a rough action (RAG query with context retrieval), so the general purpose is inferable. However, 'RAG query' is vague about what the tool actually does—retrieve chunks, generate an answer, or both—and it gives no differentiation from the sibling lancedb_search, which an agent would reasonably confuse it with.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus lancedb_search, lancedb_status, or lancedb_version. No prerequisites, no conditions or exclusions are stated, leaving the agent to infer the choice from the name alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.