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

Annotations only say non-readonly, non-destructive, closed-world. The description goes well beyond: it names the invariant (exactly one default, observable via pipeline_is_default in list_pipeline_stages), states existing deals do not move, and states the idempotent no-op behavior on the current default. An agent knows exactly what will and won't change.

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?

Front-loaded with the verb and resource, then the downstream effects. The single long sentence packs several distinct facts (affected channels, invariant, no-move, no-op), which is dense but every clause carries meaning; a short bulleted split would be slightly easier to scan.

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 one-parameter mutation with no output schema, the description covers the essential behavioral surface: effects, invariant, and idempotency. Return value/permission requirements are not described, but there is no output schema to explain away and the annotation set covers safety.

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% and the schema already says the pipeline_id comes from list_pipeline_stages. The description reinforces the source and clarifies that it identifies a single pipeline, but adds little syntax or format detail beyond the structured field.

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 ('Make a pipeline the default') and then enumerates exactly which inbound paths are affected and what happens to them ('land in its first stage from now on'). It is clearly distinguished from rename_pipeline and reorder_pipeline_stages by describing the default-state semantics rather than structural edits.

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?

Gives clear conditions: it applies to new leads/deals without their own pipeline, and explicitly says calling it on the current default changes nothing. It also clarifies the invariant that exactly one pipeline can be default. It stops short of naming a sibling to use for renaming or reordering, but the usage context is unambiguous.

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