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

Annotations already establish the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds meaningful scope information ('signed-in user's') beyond the annotations. It says nothing about pagination, ordering, or result size, which are the remaining behavioral gaps for a list tool.

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 sentence that front-loads the verb and resource and then supplies the rationale. Every clause earns its place; nothing is redundant with the title or name.

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 zero-parameter, read-only list tool with no output schema, the description states what is returned (Projects plus active Site details) and the caller's scope, which is sufficient to call it correctly. It stops short of describing the shape or ordering of results, and does not resolve the overlap with list_projects.

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?

The schema declares zero properties, so there are no parameters to document and the baseline of 4 applies. The description correctly avoids inventing parameter semantics that do not exist.

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?

Specific verb (List) plus a well-defined resource: the signed-in user's Projects and their active Site details. The scope is unambiguous at the operation level. It does not, however, distinguish itself from the closely named sibling list_projects, leaving the agent to guess which listing is appropriate.

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 clause 'so the user can choose a target without knowing an internal Project ID' implies the tool's role (surfacing projects to select as a submission target), which is useful implied usage. But it gives no explicit when-to-use vs when-not and names no alternative among the several sibling list_* tools, so the routing guidance stays inferential.

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