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

With no annotations, the description carries the full burden and does disclose real behavior: large files truncate and signal truncated=true, and the call requires memory:read. Remaining gaps are minor (error shape on a missing path or bad ref), and the truncation flag is a genuinely useful caveat an agent would otherwise miss.

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 short sentences, front-loaded with the core action, then the truncation caveat, then the auth prerequisite. Nothing is redundant and nothing needs trimming.

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 return-shape explanation isn't required, and the description still volunteers the one return detail that matters (truncated=true) plus the permission requirement. For a three-parameter read tool this is close to complete; only failure modes for bad refs/paths are unaddressed.

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% — ref, path, and github are each documented in the schema with defaults and constraints. The description adds no syntax or format detail beyond that, so the 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?

"Read one file from a connected repo" gives a specific verb and resource, and the singular-file scope implicitly separates it from github_tree, github_repo_get, and github_code_search. It stops short of naming those siblings explicitly, so the differentiation is inferred rather than stated.

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?

The description implies when this tool applies (you have a known path and want its contents) but never states when to prefer github_tree, github_code_search, or github_repo_get instead. The only cross-reference, "Same binding errors as github_repo_get," is about error behavior, not tool selection.

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