perplexity-research — Brain-Augmented Web Research

Convention: see conventions/quality.md for citation rules; every claim from web research lands with a verifiable citation, not a paraphrase.

Convention: see conventions/brain-first.md for the lookup chain. This skill ENFORCES brain-first by sending brain context as part of the Perplexity prompt — the web search focuses on the delta between brain knowledge and current web state.

What this does

Combines existing brain knowledge with Perplexity's web search. The agent sends brain context about a topic into a Perplexity query; Perplexity searches + reads + synthesizes multiple pages with citations, focused on what's NEW relative to the supplied context.

The key insight: Perplexity doesn't just search — it reads and synthesizes with citations. By sending brain context in the instructions, it knows what you already know, so it surfaces the delta instead of repeating settled fact.

When to use this vs other tools

Output structure

The research output lands as a brain page under research/<slug>.md with this structure:

---
title: "[Topic] — Research [YYYY-MM-DD]"
type: research
date: YYYY-MM-DD
brain_context_slugs: ["pages whose context was sent to Perplexity"]
recency_filter: "[hour|day|week|month|none]"
---

# [Topic] — Research [YYYY-MM-DD]

> Executive summary: 2-3 sentences on the delta between brain knowledge
> and current web state.

## Key New Developments
What's changed since the brain was last updated on this topic.

## Confirming Signals
Web evidence validating existing brain knowledge.

## Contradictions or Updates
Things that conflict with the brain — these need a closer look.

## Recommended Brain Updates
Specific page updates the user might want to make based on this research.
Each item: which page, what to add or change, source URL.

## Citations
- [Source title](URL) — accessed YYYY-MM-DD
- [Source title](URL) — accessed YYYY-MM-DD
- ...

Invocation

The skill is markdown agent instructions; the agent uses Perplexity's API directly (or a host-provided perplexity CLI if installed):

# 1. Pull brain context
gbrain get <slug>                    # or
gbrain query "<topic keywords>"

# 2. Compose the Perplexity query with brain context inline:
#    """
#    Topic: <topic>
#    Brain context (what we already know): <embedded gbrain content>
#    Find: what's NEW since 2026-MM-DD that the brain doesn't reflect.
#    Cite every claim.
#    """

# 3. Call Perplexity's Agent API (or the host's perplexity binary). The
#    Sonar chat-completions endpoint (/chat/completions with
#    "model": "sonar-pro") is being retired and refuses migrated accounts
#    with 403 agent_api_migration_required; use POST /v1/agent:
#    curl https://api.perplexity.ai/v1/agent \
#      -H "Authorization: Bearer $PERPLEXITY_API_KEY" \
#      -H "Content-Type: application/json" \
#      -d '{"preset": "low", "instructions": "Cite every claim.", "input": "..."}'
#    Read the answer from the output item with "type": "message" (SDKs
#    expose it as output_text) and the citations from the search results
#    in the output array; inline [n] markers refer to them.

# 4. Write the structured research page via put_page:
gbrain put research/<slug>      # via the put_page operation

# 5. Cross-link entities mentioned (people, companies) per Iron Law.

Presets

Default to low. Drop to fast for bulk / cron contexts where cost matters more than depth. Perplexity does not publish a fixed per-request price for presets; check its pricing page before running bulk jobs.

Integration patterns

Entity enrichment

Called by skills/enrich/SKILL.md when an entity page (person, company) needs current web context:

BRAIN=$(gbrain get people/<slug> 2>/dev/null)
# Send <slug>'s page content as brain_context to Perplexity, get current
# news / role / context, then update the brain page with what's new.

Deal / company monitoring (cron)

For each active item under deals/ or companies/:

# Weekly: pull recent news per company; flag changes for review.

Morning briefing

Replace raw web_fetch calls in briefing pipelines with this skill so the agent doesn't re-narrate already-known facts.

Recency filter

Pass the recency filter on the web search tool: "tools": [{"type": "web_search", "filters": {"search_recency_filter": "week"}}] with hour | day | week | month | year. Useful for news-cycle topics; omit for evergreen research. Record the value as recency_filter in the page frontmatter.

When it fails

Follow the agent operator protocol for any gbrain error code, exit code, [AGENT] block or notice block. Specific to this skill:

• PERPLEXITY_API_KEY missing or rejected: tell the user the web arm cannot run; answer from the brain only and say so.
• rate_limited: retry after the stated delay; for bulk work drop to the cheaper model rather than looping.
• The brain-context search is empty with a degraded notice: the "what's new vs what the brain knows" diff is unreliable; say the brain side was keyword-only.

Anti-Patterns

• ❌ Sending NO brain context. Then it's just a search — use web_fetch instead.
• ❌ Truncating the brain context. The whole point is "knows what you know." Send dense context.
• ❌ Discarding citations. Every claim in the output must have a URL.
• ❌ Skipping the cross-link step when entities are mentioned. Iron Law.

Environment

• PERPLEXITY_API_KEY set in the agent's environment (or in ~/.gbrain/.env).
• Optional: install Perplexity's official CLI for richer streaming output.

Related skills

• skills/academic-verify/SKILL.md — wraps perplexity-research for citation-verified academic claim checking
• skills/enrich/SKILL.md — calls perplexity-research as part of the entity-enrichment loop
• skills/data-research/SKILL.md — structured-data trackers (different shape: parameterized YAML recipes, not free-form research)

Contract

This skill guarantees:

• Routing matches the canonical triggers in the frontmatter.
• Output written under the directories listed in writes_to: (when applicable).
• Conventions referenced (quality.md, brain-first.md, _brain-filing-rules.md) are followed.
• Privacy contract preserved: no real names, no fork-specific filesystem path literals, no upstream-fork references.

The full behavior contract is documented in the body sections above; this section exists for the conformance test.

Output Format

The skill's output shape is documented inline in the body sections above (see "Output", "Brain page format", or equivalent). The literal section header here exists for the conformance test (test/skills-conformance.test.ts).