Get project level merge request rule

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds genuinely non-redundant behavior: the return shape (a wrapper containing the original response plus an ApprovalRule model) and the error contract (MissingParameterError, ParameterError). Most valuable is the implicit disclosure that project_id and approval_rule_id are effectively required despite the schema marking nothing required. It does not mention auth scope or permissions, hence not 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?

The intent sentence is front-loaded and efficient, but the boilerplate Args/Returns/Raises scaffolding is largely template text and the kwargs line ('e.g., project_id, approval_rule_id') is vague and hedged. It is not bloated, but several lines do not earn their 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?

For a tool exposed with 13 parameters, zero schema descriptions and no output schema, the description covers only 2 parameters and leaves the agent guessing whether the rest are inputs to this call or leaked from a sibling operation. The return type is described, which is a plus, but the parameter surface is substantially unexplained.

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 0% across 13 parameters, so the description must carry the burden and it does not: only project_id and approval_rule_id are named, and only in the docstring's kwargs gloss and Raises section. The remaining eleven parameters (name, user_ids, approvals_required, applies_to_all_protected_branches, etc.) are never mentioned, and the description does not tell the agent that they are likely irrelevant to a read operation.

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?

The first sentence states a specific verb and resource: retrieving details of one project-level merge request approval rule. That is unambiguous on its own, but it does nothing to separate this tool from near-identical siblings such as gitlab_get_project_level_merge_request_rules (the list variant) or gitlab_get_project_level_rule (the non-merge-request rule).

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?

There is no statement of when to use this tool versus the plural list sibling, the group-level rule tool, or the merge-request-level rules tool. The only usage-adjacent content is an error condition, which tells the agent what fails, not what to choose.

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