# Description Quality Reference

Source: agentskills.io — optimizing-descriptions

## How triggering works

At startup, agents load only the `name` and `description` of each skill. When a user's task matches a description, the agent reads the full `SKILL.md` into context. **The description carries the entire triggering burden** — the body is never seen until after triggering.

Agents typically consult skills only for tasks requiring knowledge beyond their defaults. Specialized knowledge — unfamiliar APIs, domain-specific workflows, uncommon formats — is where description wording makes the difference.

## What a good description does

- **Imperative phrasing** — "Use when..." not "This skill does...". The agent is deciding whether to act.
- **User intent, not mechanics** — describe what the user is trying to achieve, not how the skill works internally.
- **Err toward being pushy** — explicitly name contexts where the skill applies, including cases where the user doesn't name the domain: "even if they don't mention X explicitly."
- **Specificity over vagueness** — "parses and validates OpenAPI specs" beats "helps with APIs."
- **Near-miss exclusions** — add "Do not use when..." only if a near-miss skill exists that could steal activations. Use strong near-misses (queries that share keywords but need something different), not weak ones ("write a fibonacci function").
- **Hard limit: 1024 characters** — descriptions grow during revision; check length before finalising.

## Before / after

```yaml
# Weak
description: Process CSV files.

# Strong
description: >
  Analyze CSV and tabular data files — compute summary statistics,
  add derived columns, generate charts, and clean messy data. Use when
  the user has a CSV, TSV, or Excel file and wants to explore, transform,
  or visualize the data, even if they don't explicitly mention "CSV" or
  "analysis."
```

The strong version names capabilities precisely and broadens applicability beyond explicit keyword matches.

## Auditing guidance

Flag as FAIL if:
- Phrasing is descriptive ("This skill...") not imperative ("Use when...")
- Capabilities are vague ("helps with APIs") — require precise verbs and nouns
- No indirect trigger coverage when indirect cases clearly exist
- No near-miss exclusions when a sibling skill could plausibly steal activations
- Length exceeds 1024 characters

Flag as SUGGESTION if:
- Indirect trigger coverage exists but could be more specific
- Near-miss exclusions are present but target weak near-misses only