Design model

Platform spec article

Design model

Back to Console capabilities ◎ Open feature in platform map

Spec standingStandard

Owner

Piotr Mikstacki pmikstacki@cybernomad.it

Submitter

Piotr Mikstacki pmikstacki@cybernomad.it

Current document

ADRs (3)

1. 0020-no-color-semantics NO_COLOR disables color Accepted

   Any non-empty NO_COLOR strips ANSI emission.

   Context

   Users and CI expect no-color.org semantics for accessibility and logs.

   Decision

   Rule	Detail
   NO_COLOR	Non-empty value must force ShouldEmitAnsi() false
   Reference	no-color.org

   Consequences

   Capability probes and markup render paths consult the same gate.

   Verification anchors

   CapabilitiesTests.bd; Console/Capabilities.bd.

   Open full ADR page

2. 0021-colorterm-truecolor-upgrade COLORTERM upgrades to TrueColor Accepted

   COLORTERM presence selects TrueColor when color allowed.

   Context

   Modern terminals advertise truecolor via COLORTERM without breaking NO_COLOR.

   Decision

   Rule	Detail
   Probe	COLORTERM set → TrueColor when color not stripped
   FORCE_COLOR	May enable emission on non-TTY stdout

   Consequences

   EffectiveColorModel reflects env probes before SGR downgrade (see D-CORE-TERM-0003).

   Verification anchors

   CapabilitiesTests.bd.

   Open full ADR page

3. 0022-lossy-color-downgrade Lossy color downgrade Accepted

   RGB downgrades through palette ladders automatically.

   Context

   Callers should not manually pick CSI color modes per terminal.

   Decision

   Rule	Detail
   Downgrade	RGB → indexed → basic is lossy
   API	No per-sequence model selector on public helpers

   Consequences

   Styled output remains readable on Basic16 hosts without author branches.

   Verification anchors

   AnsiSgrGoldenTests.bd; capability + SGR integration.

   Open full ADR page

Articles

• Contracts and edge cases MUST rules for capability probing and color stripping. article Standard Reviewed Thu May 21
• Design model Capability record, color models, and environment-driven probing. article Standard Reviewed Thu May 21
• Examples Checking capabilities before custom styling. article Standard Reviewed Thu May 21
• Flow and algorithm Probe and strip algorithms for terminal capabilities. article Standard Reviewed Thu May 21
• Verification and traceability Tests and sources for capability probing. article Standard Reviewed Thu May 21

History

0 revisions (git unavailable at build; counts may be empty)

Open full history on GitHub

No commits recorded for this path.

Completeness

OKfeature · 3 SpecSection(s) · 1 H2 heading(s)

Section id	Required	Found
what-this-feature-specifies	yes	yes
implementation-anchors	yes	yes

Full tree: run pnpm verify:platform-spec-layout (writes src/generated/platform-spec-layout-report.json).

Related spec docs

• Feature
  Console capabilities

  Parent feature hub

Purpose

Document design model for the Console Capabilities feature: role-specific normative detail beyond the feature hub.

Canonical references

• Feature hub: Console Capabilities
• Sibling articles in this bundle (design model, contracts, flow, examples, verification)

Detailed behavior

Capabilities record

Field	Meaning
isTty	stdout (fd 1) is a terminal
colorDisabled	NO_COLOR set
colorForced	FORCE_COLOR set
model	Probed ColorModel before strip

ProbeStdout() composes the record from Platform.Terminal.IsAtty(1) and environment helpers.

ColorModel ladder

Variant	Typical trigger
Basic8	Reserved for minimal terminals
Basic16	Default when stripped or TERM=xterm-color
Indexed256	TERM=xterm-256color or generic TERM set
TrueColor	COLORTERM set (e.g. truecolor)

Ansi.Sgr maps requested RGB to the effective model after ShouldStripColor.

Interaction with ANSI emission

ShouldEmitAnsi() is equivalent to !ShouldStripColor(ProbeStdout()). All gated escape helpers consult this predicate; see ANSI escape model / flow and algorithm.

Verification

See the verification and traceability article in this bundle and compiler/corelib/beskid_corelib/tests/corelib_tests/src/console/.

Related topics

• Parent feature hub and Terminal and console area