照片 EXIF（拍摄时间/GPS/机型）

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does reasonably well: it is clearly a read-only inspection, it discloses the extra computed output (是否可信 comparison against file mtime), and it explains that passing a directory switches to a batch aggregation with a sampled subset governed by limit. It does not say what happens for non-JPEG files, images lacking EXIF, or missing paths, which for a read tool with no annotations is the main remaining gap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight clauses: what is extracted, the mtime-credibility signal, then the directory batch behavior, then the intended use. Output contents are front-loaded and nothing is redundant or filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description compensates by enumerating the returned EXIF fields and the batch summary statistics (count with EXIF, time span, model distribution), which is what an agent needs to decide to call it. Missing only failure-mode behavior and any note on cost of scanning large directories beyond the limit cap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters are already documented, including the default 50 and cap 200 for limit. The description adds the meaning of the file_path dual mode (file vs directory → single report vs batch summary), but restates rather than extends the limit semantics. Baseline 3 applies when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource (读取 JPEG 的 EXIF) and enumerates exactly what is extracted: DateTimeOriginal, camera model, GPS, aperture/shutter/ISO/focal length, pixel dimensions, plus a file-mtime credibility check. The directory-mode batch summary is spelled out too, and the JPEG constraint implicitly separates it from the video sibling get_video_info.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a use case (用于按真实拍摄时间整理相册) and implicitly scopes it to still images, which helps against get_video_info and probe_dir. But it never says when NOT to use it, never names an alternative (e.g. probe_dir for non-EXIF metadata listings), and does not state prerequisites such as the file needing to be a JPEG with an EXIF block.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.