docs: add token-cost budget to grep-verification guidance

.cursor/rules/codegraph.mdc

@@ -26,7 +26,7 @@ Use codegraph for **structural** questions — what calls what, what would break
 ### Rules of thumb
 
 - **Answer directly — don't delegate exploration.** For "how does X work" / architecture / trace questions, answer with 2-3 codegraph calls: `codegraph_context` first, then ONE `codegraph_explore` for the source of the symbols it surfaces. Codegraph IS the pre-built index, so spawning a separate file-reading sub-task/agent — or running a grep + read loop — repeats work codegraph already did and costs more for the same answer.
-- **Trust codegraph results.** They come from a full AST parse. Do NOT re-verify them with grep — that's slower, less accurate, and wastes context.
+- **Don't grep-verify codegraph results — each unnecessary verification costs ~800 tokens.** They come from a full AST parse. Budget: 3 grep verifications per task. Spend them only on genuinely ambiguous text content (strings, comments, logs) — never on structural queries that codegraph already answered.
 - **Don't grep first** when looking up a symbol by name. `codegraph_search` is faster and returns kind + location + signature in one call.
 - **Don't chain `codegraph_search` + `codegraph_node`** when you just want context — `codegraph_context` is one call.
 - **Don't loop `codegraph_node` over many symbols** — one `codegraph_explore` call returns several symbols' source grouped in a single capped call, while each separate node/Read call re-reads the whole context and costs far more.

src/installer/instructions-template.ts

@@ -44,7 +44,7 @@ Use codegraph for **structural** questions — what calls what, what would break
 ### Rules of thumb
 
 - **Answer directly — don't delegate exploration.** For "how does X work" / architecture / trace questions, answer with 2-3 codegraph calls: \`codegraph_context\` first, then ONE \`codegraph_explore\` for the source of the symbols it surfaces. Codegraph IS the pre-built index, so spawning a separate file-reading sub-task/agent — or running a grep + read loop — repeats work codegraph already did and costs more for the same answer.
-- **Trust codegraph results.** They come from a full AST parse. Do NOT re-verify them with grep — that's slower, less accurate, and wastes context.
+- **Don't grep-verify codegraph results — each unnecessary verification costs ~800 tokens.** They come from a full AST parse. Budget: 3 grep verifications per task. Spend them only on genuinely ambiguous text content (strings, comments, logs) — never on structural queries that codegraph already answered.
 - **Don't grep first** when looking up a symbol by name. \`codegraph_search\` is faster and returns kind + location + signature in one call.
 - **Don't chain \`codegraph_search\` + \`codegraph_node\`** when you just want context — \`codegraph_context\` is one call.
 - **Don't loop \`codegraph_node\` over many symbols** — one \`codegraph_explore\` call returns several symbols' source grouped in a single capped call, while each separate node/Read call re-reads the whole context and costs far more.

src/mcp/server-instructions.ts

@@ -30,9 +30,7 @@ then ONE \`codegraph_explore\` for the source of the symbols it surfaces.
 Codegraph IS the pre-built search index — so delegating the lookup to a
 separate file-reading sub-task/agent, or running your own grep + read
 loop, repeats work codegraph already did and costs more for the same
-answer. Reach for raw Read/Grep only to confirm a specific detail
-codegraph didn't cover. A direct codegraph answer is typically a handful
-of calls; a grep/read exploration is dozens.
+answer. Don't grep-verify codegraph results — each unnecessary verification costs ~800 tokens. Budget: at most 3 grep calls per task, spend them only on genuinely ambiguous text content (strings, comments, logs) — never on structural queries that codegraph already answered. A direct codegraph answer is typically a handful of calls; a grep/read exploration is dozens.
 
 ## Tool selection by intent