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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the description's added value is the authorization requirement (write access on the target repo) and the response shape {number, url}, both of which the agent would otherwise have to guess. It doesn't cover failure modes (duplicate titles, archived repos, rate limits), which keeps it from a 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?

Three short sentences, zero filler, with the action stated first and the permission and return-value facts following. Every sentence carries distinct 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?

For a simple four-parameter create tool with no output schema, the description covers purpose, authorization, and the return shape, which is enough to call it correctly. Minor gaps remain around error/duplicate behavior, but nothing essential is missing.

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% and each of the four parameters is documented in the schema (owner as username or org slug, repo name, title, optional Markdown body). The description adds no meaning 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?

States a specific verb+resource pair ("Create a new issue") plus the hosting platform, which is unambiguous and separable from siblings like merjax_close_issue, merjax_comment_issue, or merjax_search_issues. It stops short of naming a sibling or stating scope boundaries (e.g., single repo, no bulk creation), so a 4 rather than a 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?

The description gives a prerequisite ("Requires authenticated caller with write access on the target repo") but no when-to-use/when-not-to-use guidance and no routing to alternatives such as merjax_comment_issue for adding to an existing issue. Usage is implied by the verb, not explained.

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