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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful non-structured behavior: per-call pricing ($0.002 USDC via x402 on Base/Solana/Arc), that failed calls are not charged, and result ordering (newest updated first). It does not mention pagination or rate limits.

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?

Purpose and return shape are front-loaded in a single dense sentence, followed by the pricing caveat. Slightly packed but no filler; the price detail earns its place because it affects whether an agent should call it.

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?

With an output schema present, the return-field listing is a bonus rather than a requirement, and annotations cover the read-only/open-world profile. Adding payment terms, failure billing behavior, and sort order makes this complete for an agent deciding and calling correctly.

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%, so all five parameters (including defaults for type and limit) are already documented in the schema. The description restates default state behavior and sorting but contributes no additional parameter syntax or constraints, 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?

Specific verb and resource: 'Issues or pull requests of a GitHub repository, searched by words and state', plus a summary of returned fields. It clearly conveys what is fetched, but it never names the sibling it sits beside (github_search, github_repo, github_releases), so an agent must infer which GitHub tool to pick.

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 only implied through the query/state phrasing; there is no explicit when-to-use statement or routing advice against github_search or github_repo. An agent can infer that words+state filter issues, but nothing tells it when this beats the alternatives.

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