Get an issue

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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), and the description adds genuine behavioral detail beyond them: PR numbers are accepted here and flagged via `pull_request: true`. It doesn't cover failure modes (e.g., 404 for a nonexistent index) or pagination/auth, so a 4 rather than 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?

A single front-loaded sentence carries purpose, addressing, field delta, and the PR-number caveat with no filler. The em-dash aside makes it dense on first read but every clause earns its place.

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?

There is no output schema, so the description must characterize the return value — it does so by describing fields relative to list_issues plus body, locked, due_date and ref, which is enough for an agent to know what it gets. Error and empty-result behavior are the only meaningful omissions.

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 100%, with each of the three parameters documented inline, so the baseline is 3. The description's '(owner/repo/index)' notation restates the composite key but adds no format or constraint detail beyond the schema.

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 — 'Get one issue by number from a repository' — and defines the addressing triple (owner/repo/index). It also distinguishes itself from both list_issues (whose fields it extends) and get_pull_request, so an agent can pick it without opening a schema.

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?

Explains the shared issue/PR numbering and that a PR number is valid here, plus that get_pull_request is the place for branches and merge state — which effectively routes the agent. It stops short of an explicit 'use list_issues to browse, use this to fetch one' statement, so not a full 5.

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