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

Annotations already declare this is a non-read-only, non-idempotent but non-destructive mutation with no open-world access, so the safety profile is covered. The description adds the useful notion that the effect is "windowed" (implying start/end scoping), but says nothing about what happens if the effect is applied twice, how it interacts with an existing same-kind effect, or what the call returns.

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?

A single front-loaded sentence with the core action stated first and the effect list trailing as amplification. It is efficient, though the long enumeration partially duplicates the enum already present in the schema rather than adding new information.

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?

A non-destructive, reversible add-effect tool with six mostly self-describing parameters and no output schema does not require deep prose. The description gives enough to select and invoke it, though it omits start/end time-base and intensity range details that would prevent malformed calls.

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 only 33%: project_id and motion_motif are documented in-schema, but start, end, intensity and kind are not. The description names effect kinds (mirroring the enum, which already exists) yet never explains the window semantics of start/end, the units or sensible range of intensity, or that start/end express a time range in the timeline.

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 ("adds a windowed finishing effect to the program picture") and enumerates concrete effect kinds that map onto the `kind` enum. It does not, however, distinguish itself from close siblings like add_finish or add_region_effect, so an agent cannot tell which of the overlapping "effect" tools to reach for from the description alone.

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 when-to-use or when-not-to-use guidance, no prerequisites, and no mention of the obvious alternatives (add_finish, add_region_effect, set_intensity) or the undo path (remove_stylize). Usage is only implied by the list of effect names.

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