Lower model cost for coding agents
With the Loom plugin and code index, Claude Code answered questions about the ClickHouse codebase at 6% to 21% lower model cost than without it on all three measured question sets. The savings were 20% on 24 answer-graded questions (answer quality 0.84 against 0.78), 21% on 36 conceptual questions and 6% on 24 multi-hop questions, where tracing a bug to its fix on a release branch cost the same both ways.
What was measured
Both arms ran Claude Code (claude-sonnet-5) on the same checkout: one plain session, one
with the Loom plugin and the coding toolset. Cost is the whole session's model bill and
excludes Loom's own server-side model calls, hosting and indexing. The comparison measures
the plugin as a whole; it does not separate the code index from memory. Results are
specific to the tested workloads. With Loom a question takes longer on the clock: the
plugin's per-prompt search and the MCP round trips add latency. How per-question cost is
compared against run-to-run noise is on the results page.
With and without Loom has every set, the
protocol and the artifacts, and evaluate Loom shows how
to measure it on your own repository.
For memory read by a model instead of a whole chat history, see agent memory.
How the plugin is designed to save
- Index answers instead of file reads.
code.symbol,code.callersandcode.searchreturn the lines that answer a structure question. Code index - Saved context instead of rediscovery. Decisions and findings a session saves are loaded at the next session's start. Shared memory
Loom also records what it spends on embedding and LLM calls per operation. Cost and usage