brew

/brew — Fellow Aiden profile factory

Turn a coffee bag into a well-tuned Fellow Aiden profile, then stop. You pick the volume, read the grams, and grind at the machine — the profile carries everything needed for that. Brewing and scheduling are not this skill's job: they live in the MCP (brew_now, create_schedule) and you reach them by saying "brew now".

When to use

• User names a coffee bag (roaster, origin, roast) and wants it dialed in.
• User shows a photo of a bag.
• User says /brew.

Required input

Just the bean — from text or a photo. Ask only if roast or origin is genuinely ambiguous; never guess them. Do not ask for a target volume — the profile is volume-agnostic (a profile_type=0 profile carries both single-serve and batch settings, and the device shows the dose once you pick millilitres).

Flow

1. Identify the bean (photo/text), incl. dimensions: varietal, process, roast, origin.
2. Check coffee://profiles for an existing match — roaster + coffee-name substring (e.g. "Intermission" + "Spring Bloom"). User profiles live in the Custom folder. If one matches, reuse it and say so; skip the rest. Only create fresh if there's no match or the user asks for a new one.
3. Clone a template drop from coffee://profiles via the decision tree in references/profile-heuristics.md.
4. Palate pre-flight — call query_palate(varietal, process, roast_level, origin, altitude_masl) for the user's tasting history of similar beans (see below).
5. Apply nudges: light-natural/Geisha overrides (below) + roast-delta, plus the palate correction from step 4 if its confidence is meaningful.
6. Derive the two grind numbers — single-serve and batch (below).
7. create_profile with profile_type=0, °C temps, and the grind-span title.
8. Print the recipe card. Stop.

Palate pre-flight (step 4)

query_palate returns {tendency, confidence, n, neighbours} — tendency is the similarity-weighted mean of the signed tasting axes (−2…+2) across the user's similar past brews. If n ≥ 2 and confidence is meaningful, translate the tendency into a template nudge via the fault→lever mapping and say why:

"Your last 3 Geisha naturals averaged sour (+1.5 acidity) — starting one grind finer and ratio 16.0 instead of the template's 16.5."

Lever directions: acidity + (trends sour) → grind finer / ratio tighter; bitterness + (trends bitter) → grind coarser; strength +/− → ratio looser/tighter. If n = 0 or confidence is low, proceed from the template silently — never invent history.

Non-negotiable MCP values

These are the traps a fresh agent falls into. Always use these.

Param	Value	Why
profile_type	0 (int)	0 = universal (accepts both batch and ss pulse fields). 1 is Cold Brew only; the Fellow cloud rejects all pulse fields when type ≠ 0.
Temperatures	°C	Celsius only. Range 50.0–99.0 in 0.5 steps. No Fahrenheit. Never.
ratio	water:coffee	Allowed: 14.0, 14.5, …, 20.0 (0.5 steps).
bloom_ratio	bloom-water:coffee	Allowed: 1.0, 1.5, 2.0, 2.5, 3.0.
bloom_duration	seconds, 1–120	Real profiles use 30–45. Stay in that range.
ss_pulse_temperatures / batch_pulse_temperatures	list of °C floats, length == corresponding *_pulses_number	e.g. ss_pulses_number=3 → ss_pulse_temperatures=[93.0, 93.0, 93.0].
ss_pulses_interval / batch_pulses_interval	seconds, 5–60	Use 23 for ss, 30 for batch (matches existing "drops" profiles).

A profile_type=0 profile sets both ss and batch pulse fields — that's why one profile serves any volume, and why you never ask which mode up front.

Template heuristic — clone a Fellow drop

Fellow's Fellow/ folder has three roast baselines (plocal0-2) and drops/ has ~10 curated real-world recipes. Always clone one as the starting point rather than inventing params. Full decision tree + template table: references/profile-heuristics.md.

Quick overview:

Bean profile	Template
Processing = fermented / anaerobic / natural-with-funk	d103 Black & White (light funk) or d102 Brandywine (deep funk)
Origin = East African washed (Kenya, Ethiopia w.)	d24 Regalia, Kenya Gitare AB
Origin = Latin America, light-medium	d67 Broadsheet, Jorge Rojas La Roca
Origin = Latin America, standard medium (Peru, Mexico)	d105 Olympia / d108 Paloma
Origin = Brazil (chocolatey, natural)	d110 Square Mile, Sitio da Torre
Origin = Indonesia / earthy / low-acid	d106 Andytown, Indonesia Mt Ijen
Dark blend or espresso-leaning roast	d111 Square Mile, Red Brick / d112 K Brew Scruffy City
Unknown origin, standard roast	plocal0 (light) / plocal1 (medium) / plocal2 (dark)

Fetch params at invocation via coffee://profiles — don't hardcode them; IDs change.

Roast-delta adjust vs the template:

Delta	Nudge
Bean lighter than template	ratio +0.5, bloom_temperature +0.5 °C
Bean darker than template	ratio -0.5, each pulse temperature -1 to -2 °C

Keep the template's pulse pattern (flat vs descending) and count.

Delicate light naturals & Geishas

These over-extract and shed florals easily, and the drop-clone defaults lean the wrong way for them. For a Geisha or fruity light natural, override toward:

• Flat pulses + hot bloom — bloom ~96 °C, then flat pulses ~93.5–94 °C, not a descending ramp. Descending ramps tame a darker/soluble coffee's bitter tail; a dense light roast doesn't have one. Only descend if a brewed cup turns astringent.
• Ratio 16.0–16.5 — clarity-forward; the extra dilution opens the florals.
• Bloom 2–2.5× — Fellow's default is 2×; reserve 3× for very fresh, heavily degassing roasts (above ~3× actually lowers extraction). Don't reach for 3× by reflex.
• Grind finer — see the Geisha row under Ode Gen 2 grind.

Ode Gen 2 grind — derive two numbers

The profile is volume-agnostic, but the right Ode Gen 2 grind isn't: single-serve grinds finer than batch (larger dose → deeper bed → coarser to avoid over-extraction). So derive both, and put both in the title. Scale 1.0–11.2, lower = finer.

Roast	Single-serve (≤450 ml)	Batch (451 ml+, climbs with size)
Light	5	7
Medium	6	7
Dark	7	8

• Single-serve is one stable number across its whole 150–450 ml range (shallow bed).
• Batch climbs with carafe size — start at the low end of its range and go coarser as the carafe fills. There's a step (not a slope) at the basket change: nobody grinds the in-between number.
• Delicate light naturals / Geishas grind FINER than the table: Fellow's own natural-Geisha call is single-serve 3.1–4.2 (use ~4), batch 6–9 (source). Corroborated by owners (single-serve ~4–6, batch ~8–8.5). So a Geisha title is 4-8.

These are native Gen 2 numbers — do NOT translate from Gen 1. Prefer Fellow's first-party per-coffee call when the user has it.

Water (BWT magnesium-forward filter)

Leo's brew water is BWT magnesium-mineralised — calcium stripped, magnesium added, soft, near-neutral pH.

• Magnesium-forward water amplifies perceived sweetness, fruit and floral — it flatters fruity light naturals / Geishas.
• "Magnesium over-extracts" is marketing, not science. Do NOT grind coarser to compensate for the water.
• The real risk is low alkalinity → sharp / sour ("bright front, empty middle"), because softening strips buffer. If a cup reads sharp or thin, fix it with a weaker ratio (~1:17) or by adding buffer (toward GH 50–70 / KH ~40 ppm) — never by changing grind.

Title rule — lead with the grind span

The first token of the title is the grind span <SS>-<batch>, so you can read the grind straight off the device's profile list:

4-8 Intermission Geisha Colombia
│ └── batch grind  (climb from here as the carafe fills)
└──── single-serve grind

• Left number when you brew single-serve; start at the right number and climb for batch.
• ASCII hyphen only. The fellow_aiden library validates with TITLE_REGEX = [A-Za-z0-9 !@#$%&*\-+?/.,:)(]+ and fullmatch — so ~, →, –, ·, _, [], {}, ", ' are all rejected before the request leaves the machine. Of the range glyphs, only -, /, : are legal; use -.
• Max 50 chars. Format: <SS>-<batch> <Roaster> <Origin> or … <Coffee Name>.

Recipe card output

After create_profile, print this and stop (no checklist, no brew-now nudge — those happen at the machine):

Created: 4-8 Intermission Geisha Colombia

Grind (Ode 2):  4 single-serve  ·  6-9 batch (climb with size)
Ratio:          1 : 16.5
Bloom:          45 s @ 96 °C  (2.5×)
Pulses:         3 flat @ 94 °C
Template:       d110 Square Mile (Brazil natural) + Geisha overrides

Synced to Fellow cloud. Pick ml at the machine.

Mode boundary (informs the grind numbers only)

Fellow's basket split is single-serve 0–450 ml, batch 451 ml+. The single-serve basket physically changes to the flat batch basket at that line — that's the step in the grind, and the only reason the boundary matters here. (You still never ask the volume.)

Error handling

Case	Handling
Bean info ambiguous	Ask. Don't guess origin/roast.
Existing profile matches the bag	Reuse it; report the title + id. Don't duplicate.
Fellow cloud 400	Surface the upstream message array verbatim. Common cause: profile_type ≠ 0 with pulse fields set, or an out-of-charset title.

Out of scope

This skill creates the profile and stops. Handled elsewhere:

• Brewing & scheduling — the MCP brew_now and create_schedule tools. Reach them by saying "brew now"; the server does duration, timezone and READY-time math.
• Device-state checks / pre-brew checklist — do at the machine.
• Target volume / dose / grams — the device shows the dose once you pick ml.
• Tasting-note iteration, persistent journal — planned for a v2 journal context.

Red flags

• About to pass profile_type=1 with pulse fields → stop, use 0.
• About to use °F → stop, Fellow is °C only.
• Guessing origin or roast from a bag → stop, ask the user.
• About to ask for a target volume / pick a mode → stop, the profile is volume-agnostic; you only derive two grind numbers.
• About to read coffee://device, render a checklist, estimate duration, or call brew_now as part of /brew → stop, all out of scope; this skill ends at the recipe card.
• Skipping the coffee://profiles dedup check → stop, reuse before creating.
• About to finalize a profile without calling query_palate for a bean whose dimensions you know → stop, check palate history first and pre-correct (step 4).
• Inventing pulse temps / ratios from nothing → stop, clone a Fellow drop first.
• Using the table's "light" grind (5 SS) for a Geisha / delicate natural → stop, those grind finer — Fellow's own call is ~4 SS.
• Giving a light natural / Geisha a descending pulse ramp → stop, flat ~94 °C suits them.
• Translating Gen 1 grind numbers to Gen 2 → stop, the table is already Gen 2.
• Grinding coarser "because the water is magnesium-forward" → stop, unfounded.
• Naming a profile without the grind span as its first token, or with a non-ASCII glyph (~, →, ·, en-dash) → stop, lead with <SS>-<batch> using a plain hyphen.