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    Using Rocky: agentic-assisted programming value report

    Same feature, same model: about 255k to 89k tokens (about 65%), discovery down 89%, Sonnet about $1.62 to $0.85. Side-by-side without vs with Rocky MCP on a real production React monorepo.

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    For engineers and leads using Cursor or Claude on real repos, solo or on a team.

    Connecting Rocky (handbook plus devkit gateway) changes agentic-assisted work: implement a feature, add tests, pass review, open a PR. You do not need a private team server. The public handbook applies to your repo.

    Full source doc: using-mcp-devkit-report.md. Product intro: I shipped Rocky.

    Side-by-side

    Same kind of task everywhere: implement or fix something in the user's repo, then get it review-ready.

    Without Rocky MCPWith Rocky MCP
    What the AI can useSearch, read files, terminal onlySame, plus handbook (devkit://handbook/...) and devkit actions
    ConventionsWhatever the model guesses or old chat memoryShared agents and rules (hexagonal React, tests, PR gate, ...)
    DiscoveryMany greps and 10-20+ file readscodebase-discovery plus graphify summary
    What to testManual hunttest_gap_finder gives a short gap list
    Blast radiusGuess from the diffchange_scope_analyzer on a changed path
    Run testsOften the full suite every timerepo_test / scoped commands when the repo allows
    Lint feedbackPaste long yarn lint outputrepo_lint summary
    Before PRHope CI catches issuespre_pr_quality_gate returns ready / not_ready
    Handbook tokens (disciplined)N/AAbout 4k-6k for how-it-works, discovery, and 2 reads
    Typical session tokens (estimate)About 150k-300k on a medium featureAbout 70k-150k (about 40-50% less, directional)
    Solo without "the team"?You still need conventions somewhereConnect hosted Rocky. No org repo required.
    CI on mergeYour pipelineSame. MCP does not replace CI.

    Token ranges are directional estimates for a medium feature. Log two comparable sessions in your org if finance needs proof.

    Same five phases

    PhaseWithout MCPWith Rocky MCP
    1. DiscoverGrep and read many filescodebase-discovery, graphify skim, optional change_scope_analyzer
    2. ImplementYou still write code in the editorSame. MCP does not write for you.
    3. TestFull suite or guess which filestest_gap_finder plus targeted repo_test
    4. Lint / styleTerminal spam in chatrepo_lint plus handbook rules
    5. Before PRSubjective "looks fine"pre_pr_quality_gate plus pr-quality-gate agent

    Measured example (same MCP workflow)

    Numbers from a real session on a large client project (production React monorepo): add Vitest and Playwright for table filters, with vs without MCP connected.

    TaskExpand automated tests for table filters / status tracking
    RepoLarge client app (321 unit tests in the full suite)
    Typical dayDiscover, write tests, validate 8 times, lint, optional e2e

    Executive numbers

    MetricWithout MCPWith MCPNotes
    Vitest per checkAbout 29 s (321 tests)About 10 s (3 scoped files)Measured
    Vitest across 8 loopsAbout 232 s (about 3.9 min)About 77 s (about 1.3 min)From measured single runs
    Tokens per featureAbout 150k-330kAbout 70k-170kAbout 40-55% lower (estimated)
    Discovery file readsAbout 10-18 filesAbout 0-3 plus tool JSON
    OpenRouter Sonnet 4.6 per featureAbout $1.62About $0.85Same model, fewer tokens

    Tokens by phase (midpoints)

    PhaseWithout MCP (thousands)With MCP (thousands)Reduction
    Discovery12514About 89%
    Write tests7048About 31%
    Validate x82112About 43%
    graphify read174About 76%
    E2e / lint2211About 50%
    Total (midpoint)About 255kAbout 89kAbout 65%

    Discovery 125 vs 14 is the story: a briefing instead of walking every room.

    Sonnet 4.6 cost by phase (example)

    OpenRouter list rates in the source doc (May 2026): $3/M input, $15/M output on Claude Sonnet 4.6.

    PhaseWithout $With MCP $
    DiscoveryAbout $0.50About $0.08
    Write testsAbout $0.81About $0.59
    Validate x8About $0.12About $0.08
    graphify readAbout $0.05About $0.01
    E2e + lintAbout $0.14About $0.09
    TotalAbout $1.62About $0.85

    What it was like (from the AI agent)

    MCP in ~/.cursor/mcp.json is not the same as connected and green in Cursor. Config is not connection.

    Without Rocky: semantic search and grep across the repo, conventions inferred from random files, full suite on repeat, no structured ready / not_ready. You can finish. It is slower, noisier, and more expensive in tokens.

    With Rocky: devkit-start-task, then the router, then 2-3 handbook reads. codebase-discovery and graphify policy. Scoped repo_test / repo_lint. test_gap_finder. pre_pr_quality_gate. Same outcome, less thrashing. Context goes to your code, not to reinventing process.

    For managers

    Does MCP change the app or CI? No. Does it change how the AI works? Yes: shared conventions, targeted checks, less context waste. Do you need a team deployment? No for the handbook. Connect public Rocky. Repo tools need path access to your clone.

    One line: same model, about 40-50% fewer tokens on a typical feature when Rocky is connected and the model follows the router (estimate).

    For engineers

    1. Connect devkit in Cursor. Confirm it is green.
    2. Start with devkit-start-task.
    3. Read codebase-discovery once per repo. Pick one router row. Do not read every agent.
    4. Use repo_test / scoped tests, not the full suite every message.
    5. Run pre_pr_quality_gate before opening a PR.

    Install notes: docs/INSTALL.md.

    Plain English for managers (2 minutes)

    Problem: Developers use AI to ship faster. Without shared tooling, each session rediscovers the repo, re-guesses standards, and re-runs huge test and lint cycles. That burns time and tokens. Review still catches style issues late.

    Solution in one sentence: Rocky gives the AI a team-grade handbook and small, safe repo actions (test gaps, lint summary, pre-PR gate), even for a solo developer on a public server.

    Without MCPWith Rocky MCP
    AI context on processAd hocShared playbook
    Test/lint feedbackHeavy logsTargeted actions
    Review surprisesMore commonpre_pr_quality_gate first
    Tokens per featureHigher band (about 150k-300k)Lower band (about 70k-150k)

    How to work day to day

    1. Connect Rocky / devkit MCP.
    2. devkit-start-task, then codebase-discovery, then 1 agent and 1-2 rules.
    3. Edit the user repo.
    4. repo_test / repo_lint.
    5. pre_pr_quality_gate until verdict: "ready".

    Call list_handbook only when you need a URI you do not know. Load skills when you need templates, not by default. Run graphify in the terminal. Read summary sections, not the full wiki in chat.

    Token breakdown (one table)

    BucketWithout MCP (typical)With Rocky MCP (typical)
    Repo discovery (reads + grep)About 40k-80kAbout 15k-30k
    Handbook / process0 (ad hoc prompts)About 4k-6k (disciplined)
    Test + lint logs in chatAbout 30k-60kAbout 10k-25k
    Implementation turnsAbout 80k-160kAbout 40k-90k
    Session total (mid)About 150k-300kAbout 70k-150k

    What saves tokens: router (2-3 handbook files), gateway JSON instead of pasted terminals, scoped tests, graphify summary-first.

    What does not: reading every agent after list_handbook, loading all skills, pasting graphify-out/ wholesale into chat.

    Solo vs team

    MythReality
    "Rocky is only for our org's private server."Public handbook works for any repo you open in Cursor.
    "I need the team's repo checked in."Handbook is server-side. Your code stays local.
    "Without a team I don't need conventions."Solo devs benefit more. You are your own reviewer.

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