update_milestone

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

The description discloses a non-obvious behavior beyond the annotations: 'Only the fields supplied are sent, so closing one leaves its title and due date alone.' This PATCH-like semantics is valuable even though idempotentHint and destructiveHint already cover safety. No contradiction exists between the description and annotations.

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?

Two sentences, no filler, front-loaded with the action and then the most important behavioral nuance. The example 'closing one leaves its title and due date alone' earns its place by making the partial-update semantics concrete.

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?

Given the output schema exists and the input schema documents the required and optional parameters, the description is mostly complete. It covers the core update semantics and partial-field behavior; only an explicit note about requiring an existing milestone could add a bit more, but 'in place' already implies that.

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?

With 71% schema coverage, the schema handles most parameter descriptions, but the description adds the key generalization that omitted fields are not modified. This clarifies optional parameters like state and due_on, where the schema does not explicitly say 'omit to leave alone.'

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?

The description 'Changes a milestone in place' states a specific verb and resource, clearly distinguishing this update tool from create_milestone and from set_issue_milestone, which assigns an issue to a milestone. The phrase 'in place' reinforces that it modifies an existing milestone rather than creating a new one.

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?

The description provides clear context: use this tool to modify an existing milestone, and the partial-update note explains how to preserve unspecified fields. It does not explicitly name alternatives or say when not to use it, but the intended use is not ambiguous.

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