How to brief Claude for a long document (2026)

A report, proposal or long whitepaper falls apart when you ask Claude to write it all at once. The model fills gaps with the same confidence as good paragraphs. This 25-minute flow leaves you a briefing that survives the thread: goal, audience, tone, sources and bans — before the first sentence appears.

1. Steps 1

   Gather inputs outside Claude

   Before opening the chat, write in a notes doc: document goal («convince the committee to invest in Q3»), audience («CFO with no time, knows the sector»), approximate length («8–10 pages» or «3,000 words»), must-include facts (figures, names, dates that are non-negotiable) and a tone sample paragraph if you have one. Add a «do not invent» list: unsourced figures, client names, unverified quotes. This doc is your master brief; do not improvise it in the first message.

   What you should see: A notes document with goal, audience, length, must-include facts, tone sample and a ban list.

2. Steps 2

   Open Claude with a briefing, not «write the report»

   Go to https://claude.ai and open a new chat. First message: declare the role («You are a B2B proposal writer»), the deliverable («Consulting proposal for Client X, 8 pages») and ask for the outline only: «Given the context below, propose a section outline with one purpose sentence per section. Do not draft prose yet.» Paste the step-1 brief in the same or next message. Do not ask for the full document on turn one.

   What you should see: An outline with numbered sections and one purpose sentence per block. No draft paragraphs yet.

3. Steps 3

   Approve or fix the outline before drafting

   Read the outline with an editor’s eye, not a reader’s. Is a section missing that the committee expects? Is there filler? Reply: «Drop section 4, add a risks section with max 3 bullets, merge 2 and 3.» When the outline matches your brief, confirm: «Outline approved. Do not draft until I ask section by section.» This step avoids rewriting 20 pages because the map was wrong.

   What you should see: A revised outline that matches goal and audience. Explicit confirmation that drafting has not started.

4. Steps 4

   Attach or paste sources with citation rules

   Upload PDFs, docs or paste extracts with clear labels: «SOURCE A: internal Q2 report», «SOURCE B: interview notes». In the same message set the rules: «Only use figures that appear in the sources. If data is missing, write [MISSING]. Cite the source in parentheses: (Source A, p.3).» If a fact is not in any file, do not ask for it in the draft — find it first with Perplexity and open the link.

   What you should see: Attached files or labeled blocks in the chat. Citation rules visible in the thread.

5. Steps 5

   Draft one section per message with the brief pinned

   Ask: «Draft section 1 only per the approved outline. Match the tone sample and source rules. Max 400 words.» Review that section before moving to 2. If you use Claude Projects, the brief and sources live in the project; in a loose chat, repeat key bans at the start of each section or pin the brief in the first message. Do not ask for «now the rest of the document».

   What you should see: A text block labeled Section 1. The rest of the document has not been generated.

6. Steps 6

   Run a consistency pass against the brief

   When all sections exist, paste the original brief and ask: «Compare the draft to this brief. List: inconsistent terms, tone shifts, sections that miss the goal for the stated audience.» Fix items one by one — do not accept an «all good» without looking. Unify product names, acronyms and register (informal vs formal).

   What you should see: A concrete list of inconsistencies (terms, tone, sections) and fixes applied section by section.

7. Steps 7

   Honesty check: figures and claims without a source

   Final message: «List every figure, proper name and claim that does not appear in the attached sources.» Delete or replace each item. If you needed a new fact, bring it from a source you opened — not from the model’s memory. This step is the close; without it the document is not publishable.

   What you should see: A list of unsupported claims. The final text no longer includes them, or you signed them with a verified source.