Set default intro/outro

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

With only idempotentHint in annotations, the description carries real weight and delivers: the forward-looking scope of the change, the fact that existing projects are unaffected, the clearing behavior, and the return shape { ok }. It doesn't cover permission/auth requirements or confirm whether setting a default replaces any prior default, so it stops short of fully describing side effects.

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?

Three tight clauses: what it does, the scope caveat, and the alternative tool, all front-loaded with zero filler. The return note is one token and earns its place.

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-param, non-destructive default-setting tool with a fully documented schema, the description covers scope, clearing, the sibling alternative, and the return value. Nothing an agent needs to invoke it correctly is missing.

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 100% — slot's enum and assetId's null branch are both documented in the schema, including the search_assets hint. The description's 'assetId null clears it' only restates the schema, so the baseline 3 is appropriate.

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 (set default), resource (library item as intro/outro) and an explicit scope (projects created from now on), which cleanly separates it from set_project_bumpers. An agent can distinguish this from the per-project variant without opening either 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?

Explicitly names when this applies ('projects you create from now on') and when it does not ('existing projects keep theirs'), then routes the alternative case to set_project_bumpers. The null case for clearing is also stated inline.

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