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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds genuine context beyond them by disclosing the required 'project' scope and the underlying endpoint GET /reporting/projects/{id}, which helps with auth planning and error mapping.

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 terse fragments with the key scoping fact up front and zero filler. The endpoint clause is somewhat redundant with the tool name but is short and occasionally useful for diagnostics.

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-parameter read tool there is no output schema, so the description's 'one project by id' is the only hint at the return shape, which it supplies at a high level. Combined with the annotations and fully documented schema, an agent has enough to call it correctly.

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%: id is documented with its source (smallinvoice_list_projects) and 'with' is documented with a format example. The description adds only 'by id', which the schema already covers, so the baseline of 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?

States a specific verb and resource: 'One project by id.' That implicitly contrasts with smallinvoice_list_projects, and the resource name distinguishes it from the other get_* siblings. It is clear but does not explicitly name the alternative tool.

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 only guidance is the prerequisite 'Needs the "project" scope', which tells the agent an auth requirement but not when to prefer this over smallinvoice_list_projects or how to obtain an id. Usage is implied rather than stated.

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