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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is well covered. The description adds the 'mirrored repo' context and hints that large files support slicing, but says nothing about rate limits, file-size caps, or error behavior on missing paths.

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?

Two tight sentences, front-loaded with the core action and followed by the useful slicing caveat. Nothing is wasted.

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?

For a simple read tool with full annotations and rich schema examples, this is close to complete. The absence of an output schema means the description could clarify return shape (raw file text vs metadata), a minor remaining gap.

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 coverage is 75%, so the schema documents most params including the repo enum and path example. The description's line-slicing mention aligns with line_start/line_end but adds no syntax or edge-case detail beyond the schema; baseline 3 applies.

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 (fetch) and resource (a file from a mirrored plugin source repo), and the line-slicing note clarifies the scope. It distinguishes itself from search_plugin_source by targeting a known path rather than searching, though it doesn't explicitly name that sibling.

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?

Usage is implied: you call it when you know the repo and path. There's no explicit 'use this instead of search_plugin_source' guidance or prerequisites, leaving the agent to infer when to fetch versus search.

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