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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new behavior: long files arrive truncated with a notice, and generated/binary files are refused — exactly the kind of edge-case disclosure that prevents surprise failures.

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 with no filler; the primary purpose is front-loaded and the behavioral caveats follow in a single clause. Nothing could be removed without losing information.

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?

No output schema exists, yet the description covers the main return-value risk (truncation) and excludes unreadable file types. It leaves error behavior (missing path, bad reference) unaddressed, which keeps it from a 5.

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%, with path, repo and reference each documented including defaults and format examples. The description adds no parameter-level semantics beyond what the schema already provides, 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?

States a specific verb and resource ("Read one file from a repository") and scopes it to a single file, which implicitly separates it from bulk siblings like search_code and list_code. It doesn't explicitly name those siblings, so it stops short of 5.

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 by "one file" and the repo/reference parameters, but there is no explicit when-to-use or when-to-use-something-else guidance, and no alternative is named despite many code-related siblings (search_code, list_code, code_symbols).

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