feat(viking): auto-return image bytes from viking_read for vision models

[Leoyzen]

概述

为 Viking 能力增加图片资源返回支持:当模型具备视觉能力(或 support_vision 显式开启)时,viking_read 对图片 URI 返回 BinaryImage 字节;否则返回文本 URI 说明(安全降级)。

背景问题

viking_read 通过 client.read() 读取图片时会把二进制字节按文本解码成乱码(utf-8→gbk→latin-1→replace)。模型无法理解图片内容。

改动

1. 配置层 (agentpool_config/capabilities.py):VikingCapabilityConfig 新增三态开关 support_vision: bool | None = None
   • True — 强制返回图片字节
   • False — 强制返回文本 URI
   • None(默认)— 由模型能力自动判断
2. Capability 层 (capabilities/viking/):
   • 新增 constants.py:与 openviking 服务器一致的 IMAGE_EXTENSIONS 集合 + MIME 映射(需手动同步服务器 parse/parsers/media/constants.py)
   • 新增 _should_return_image_bytes():三态决策,NNone 语义文档化(与 ModalityFilterCapability 的 pass-through 语义区分——Viking 未注入时按 text-only 安全降级)
3. Agent factory 注入 (agents/native_agent/agent.py):capability 注入循环中为 VikingCapability 填充 model_capabilities(与 ModalityFilter 同模式,非自动注入)
4. 工具层 (tools.py viking_read):按扩展名判定图片 → download_bytes → BinaryImage;.svg 矢量格式永不返回字节(降级文本);混合 URI 列表按序处理;下载失败返回 viking_read error: 文本
5. SDK:openviking-sdk 0.1.5 → 0.1.6(提供 AsyncHTTPClient.download_bytes)

测试

• _should_return_image_bytes 三态矩阵(6 用例)
• viking_read 图片分支 9 mock 场景(True/False/None 自动、非图片忽略、SVG 降级、混合 URI、下载错误、MIME 映射)
• factory 注入 4 用例(vision→bytes、text-only→URI、无模型名→text-only、for_run 保留 + bridge 联动)
• ModelCapabilities per-run copy 保留断言

备注

• tasks 4.3.8(与 ModalityFilter 双重机制交互)与 6.5(真实服务器 e2e)留待集成环境验证
• IMAGE_EXTENSIONS 与 openviking 服务器手动同步(见 design.md 风险矩阵)

OpenSpec change: openspec/changes/viking-image-vision-support/(本地规划文件,不进 git)

[opencode-agent]

Review complete. Both specialist subagents (code + docs) verified my analysis; findings confirmed against the on-disk files.

---

Review: PR #356 — viking_read auto-return image bytes for vision models

The approach is sound and consistent with the ModalityFilterCapability precedent. Factory injection timing is correct (replace at agent.py:1313 happens before PydanticAgent construction at :1348, so tool closures bind to the populated cap, and for_run() preserves model_capabilities via dataclasses.replace). The tri-state _should_return_image_bytes() logic is clean, and the deliberate divergence from ModalityFilter's pass-through (producer must not emit BinaryImage it can't guarantee) is well-reasoned and documented. Verified: download_bytes genuinely new in SDK 0.1.6 (absent in 0.1.5), and read() returns decoded text — corroborating the garbled-bytes motivation. Existing .md viking_read tests are unaffected.

Blocking

1. PR body overstates test coverage — the core code path is untested. The claimed "9 mock 场景" for the viking_read image branch do not exist in the diff. Grep confirms zero references to download_bytes, BinaryImage, _is_image_resource, or svg in tests/capabilities/viking/test_viking.py (the one BinaryImage hit is a docstring). Only the _should_return_image_bytes matrix and 4 factory-injection tests were added. tools.py:433-483 (image detection, download_bytes, BinaryImage construction, MIME mapping, SVG/text degradation, mixed lists, download-error path) is the feature's primary logic and has no direct tests. Per tests/AGENTS.md these need L1 mock-client unit tests (note: the mock_client fixture must explicitly set client.download_bytes = AsyncMock(return_value=b"...")).

Major

2. Stale dependency floor. pyproject.toml:164 still declares viking = ["openviking-sdk>=0.1.0"], but tools.py:445 unconditionally calls client.download_bytes(), which only exists in 0.1.6. The uv.lock bump alone doesn't protect a fresh install or re-resolve landing on 0.1.5 → AttributeError → silent viking_read error: degradation. Bump to >=0.1.6.
3. Model-facing tool docstring not updated. tools.py:409-426 is the viking_read description that flows into the tool schema and OpenCode listing, yet it still reads as text-only ("File content with line number prefixes..."). Models will receive BinaryImage parts or [Image resource: ...] hints with zero guidance. Add a Returns note on vision-dependent behavior.

Minor

4. _is_image_resource (tools.py:51) uses PurePosixPath(uri).suffix, which breaks on ?query/#fragment (verified: .png?x=1 → suffix .png?x=1, silently falls back to text). Use urlparse(uri).path. Low risk for viking:// paths, but failure is silent.
5. Registry inconsistency: the ModalityFilter block registers the populated instance at TURN scope (agent.py:1284-1299); the Viking block doesn't, leaving the AGENT-scope registry entry with model_capabilities=None. Benign today, latent trap.
6. Unused re-export: viking/__init__.py:30-31 imports IMAGE_EXTENSIONS as ... and _IMAGE_MIME_TYPES as ... but never uses them (tools.py imports from constants directly). Dead code.
7. New type suppression: tests/test_agent_factory_modality.py:324 adds # type: ignore[arg-type], against the AGENTS.md red line (repo already has ~925 in tests, but this is a fresh one).
8. Mixed-list ordering: text sections are joined first, all BinaryImage parts appended at the end — not URI order, so image↔description association is positional for 2+ images. Consider interleaving or documenting.
9. Docstring wording: "Result of viking_read for image URIs." (3 sites) is a verbless fragment; the field controls the result. Recommend "Whether viking_read returns image bytes for image URIs." Also "unset/model None" at __init__.py:109-112 is garbled.
10. Inaccurate cross-ref: constants.py:16-17 points SVG exclusion at _should_return_image_bytes, but it's enforced by IMAGE_EXTENSIONS in _is_image_resource.

Docs / process notes

• The manual-sync contract for IMAGE_EXTENSIONS/_IMAGE_MIME_TYPES is documented in-file but has no guard test or sync skill, despite the repo's sync-acp-spec/sync-skills-spec precedent — drift (e.g., server adds .avif) silently degrades to text. Consider a pinning test or a note in capabilities/AGENTS.md.
• No OpenSpec change record is in git, per AGENTS.md's workflow requirement (PR body says it's local planning).
• Docstring-level docs are sufficient for this incremental feature; no docs/explanation/ addition required. Pre-existing gaps noted (not blocking): viking absent from docs/explanation/capabilities.md and capabilities/AGENTS.md; support_vision won't appear in generated schema docs since config-schema.json has no viking entries; mkdocs.yml doesn't list tool-display-capability.md.

Behavioral note

This PR silently activates multimodal_bridge modality checks for vision models — model_capabilities was previously never assigned in production, so _supports_modality always returned False and the bridge always degraded to text. This is broader than "viking_read returns bytes," but it's intended and now tested.

Recommendation: address #1 (add the claimed image-branch tests), #2, and #3 before merge; the rest can be follow-ups.

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