Semantic tree

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

Annotations already declare readOnlyHint/idempotentHint/no-destructive/no-open-world, so the safety profile is covered; the description adds behavioral value by disclosing the scope of the payload (current frame, every widget, and the exact per-widget fields returned). It does not mention size limits, truncation, or pagination for large trees, which is the remaining gap.

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?

One substantive sentence followed by a two-word directive; zero filler and the most decision-relevant content (what it returns, that it is the starting point) is front-loaded.

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?

With no output schema, the description carries the return-value burden and discharges it by listing the per-widget fields. The only parameter is fully described in schema, and the read-only nature is covered by annotations, leaving nothing an agent needs to call this correctly.

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?

The single optional 'format' parameter is fully documented in the schema (100% coverage, enum values with meanings), so the schema already does the work. The description adds nothing about the format choice or the default, which is the baseline expectation when coverage is complete.

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 and resource ('Returns the semantic tree of the current frame') and enumerates exactly what each node contains (role, ID, label, value, state, bounds). That enumeration distinguishes it from siblings like screen, find, and status, which an agent can rule out without opening a schema.

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?

'Start here.' is an explicit, unambiguous entry-point instruction that tells the agent when to reach for this tool rather than a sibling. It stops short of naming alternatives or when-not-to-use conditions, so it is clear context without full routing guidance.

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