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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds one genuinely new fact not in annotations: the call is 'Free' (no credit cost). It does not say anything about result shape, pagination, or what to do when a target yields no packages.

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?

Extremely compact and front-loaded, with the cost note first and the purpose second. The fragment 'Free.' is terse to the point of being cryptic out of context, but no sentence is wasted.

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 two-parameter read-only discovery tool with annotation coverage and no output schema, the description covers the essentials of what it returns (a package tree) and why. It falls short on describing the shape of that tree — whether target_package values are names or ids — which is exactly what an agent needs to pick one for mbe_export.

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 coverage is 50%: model_id is documented in the schema, but 'target' has no schema description and only maxLength 100. The description alludes to 'a target' without explaining its accepted format or how it relates to target_package values, so it does not compensate for the undocumented parameter.

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?

Names a specific resource and scope: 'the package tree of a target'. The verb is implicit in the title 'Browse', and the description adds the downstream purpose (choosing target_package for mbe_export), which distinguishes it from siblings like mbe_list_targets that enumerate targets rather than packages.

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 implied rather than stated: the phrase 'to choose target_package for mbe_export' tells the agent this is a discovery step preceding mbe_export. However, it never explicitly says when to call this versus mbe_list_targets, nor what prerequisite state (e.g. a valid target) is required.

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