list_branches

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true and openWorldHint=true. The description adds that it does not modify files, which reinforces safety but largely repeats the annotations; it does not add details about output size, permissions or error behavior.

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 description is short and front-loaded, moving from purpose to usage to safety. The sentence 'Does not modify files' is slightly redundant with annotations, but it is not wasteful enough to hurt readability.

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 read-only listing tool with full schema coverage and rich annotations, the description covers purpose, workflow timing and safety adequately. Minor gaps remain around the optional pattern parameter and output characteristics, but the core information needed to invoke it correctly is present.

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 path, tree_name and pattern are already documented in the schema. The description adds no parameter-specific meaning beyond the general subject of branch listing.

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 branch names and types in a ROOT TTree or RNTuple. This makes the operation clear, but it does not explicitly distinguish this tool from siblings like read_branches or get_branch_stats beyond the preparatory usage note.

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 gives clear contextual guidance: use before selecting branches for reads, statistics or histograms. It does not name alternative tools or state when not to use it, but the intended workflow position is clear.

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