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

The description claims '(READ-ONLY: mutations refused)' while annotations declare readOnlyHint=false, i.e. this is a write operation that creates a new galaxy. That is a direct contradiction that could lead an agent to call a mutating fork believing it is a safe read. The description also omits what is created, whether the source is modified, and any permission requirements.

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 an inline example; nothing is padded. The trailing parenthetical is short but is the one element that does not earn its place, since it is misleading.

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 mutation with no output schema and no annotation-level detail about the result, the description says nothing about what the forked galaxy contains, whether the source partition is affected, or what happens on name collision. The read-only claim is unexplained and contradicts the annotations, leaving the agent less informed than the structured fields alone.

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 description coverage is 100%, so both 'source' and 'target' are already documented with matching examples. The description's example mapping ('guide' -> 'project-alpha') and the word 'sovereign' add a hint that the branch is independent, but nothing beyond that, so baseline 3 applies.

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 gives a specific verb and resource ('Fork an existing galaxy partition into a new sovereign galaxy branch') and a concrete example ('guide' -> 'project-alpha'). It is clear what the tool does, though it does not explicitly contrast with the sibling galaxy.create, which an agent would plausibly confuse it with.

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 explicit statement of when to fork versus when to use galaxy.create or galaxy.list, and no prerequisites or exclusions. Usage is only implied by the word 'fork', and the trailing '(READ-ONLY: mutations refused)' adds confusion rather than routing guidance.

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