get_transcript

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

With no annotations, the description carries the full burden and does so well: it discloses the default compression behavior, the citation-safety distinction between 'subtitle' and 'ai_subtitle', and explicitly states that an out-of-range page raises an error rather than silently falling back to P1. The 'degraded' field for multi-part videos is also disclosed. It stops short of covering permissions or rate limits, which keeps it from a 5.

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?

The cost ordering is front-loaded and the three usage modes are laid out as a scannable list. Heavy bold/emphasis markup and the opening warning take up space that could be tighter, but every section conveys actionable information rather than 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?

An output schema exists, so the description needn't document return shape, yet it usefully explains the two highest-stakes return fields (data_source and degraded). Combined with the mode guidance, an agent has nearly everything needed — the unmentioned max_chars is the one remaining hole in a 5-parameter tool.

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 0%, so the description must compensate, and it explains query, head_ratio, and page with real semantics (query = hit sentence ±2 context; page = which part of a multi-P video). However, max_chars (default 8000) is never mentioned at all, despite being the parameter that governs the cost tradeoff the description is built around — a notable gap.

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?

The description states a specific verb plus resource ('取字幕' — fetch the transcript) and immediately flags its default behavior (compression on). It implicitly distinguishes itself from transcribe_audio by framing itself as retrieval of existing subtitles with a data_source provenance field, but it never names that sibling or explicitly contrasts the two.

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?

It enumerates three usage modes in ascending cost order, gives a concrete value for each (head_ratio=0.2, query="关键词"), and states which one to prefer ('优先用这个'). It also warns when not to use the full-fetch mode ('长视频会非常贵，慎用'), which is exactly the when/when-not guidance an agent needs.

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