list_branches

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

The description goes beyond the readOnlyHint annotation by explicitly stating the tool does not mutate GitLab data and that missing resources, invalid identifiers, insufficient permission, and rate limits surface as errors. This gives an agent useful expectations without contradicting annotations.

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 first two sentences are strong and front-loaded, but the final sentence is boilerplate that largely repeats schema guidance and introduces an irrelevant `group_id` condition. It could be tightened without losing value.

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?

Given the read-only annotation, the error behavior disclosure, and full schema parameter coverage, the description is mostly complete for invoking the tool correctly. The main gap is the unnecessary group_id wording, but this does not block correct use when the schema is consulted.

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 the schema already documents all parameters. The description adds only generic guidance about numeric IDs or URL-encoded paths and otherwise repeats what the schema says; the mention of `group_id` is potentially confusing since the schema only accepts `project_id`.

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 description states a specific verb and resource ('List branches in project') and includes a distinguishing note to use the corresponding get tool for a single known resource. This prevents confusion with sibling tools like get_branch and list_protected_branches.

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?

It explicitly says to use this tool for a collection of resources and to choose the matching get tool when inspecting a single resource. However, it does not name the exact sibling tool or mention alternates like list_protected_branches, leaving some routing to inference.

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