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

readOnlyHint=true already tells the agent this is a safe read, and the description adds nothing behavioral on top of that — no pagination behavior, no default result size, no rate-limit or ordering notes. The only extra content is the raw API endpoint mapping, which is documentation plumbing rather than behavioral context.

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?

Extremely tight — two short clauses with the operation and scope front-loaded, and no filler. The trailing endpoint reference ("FreeAgent: GET /v2/projects") is marginally useful for docs lookup but is not something an agent needs to call the tool.

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 read-only list tool with no output schema, the description should at least signal pagination or result shape; it instead relies entirely on the schema's page/per_page descriptions. Given full schema coverage and a readOnly annotation, this is adequate but leaves clear gaps about what the listing returns and how paging behaves.

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% and all six parameters (page, per_page, sort, view, nested, contact) are fully documented in the schema. The description's "optionally for one contact" merely restates the contact parameter, adding no syntax or format detail beyond the schema, so the 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?

States a specific verb and resource ("List projects") and adds the scope qualifier "optionally for one contact", so the operation is unambiguous. It does not distinguish itself from the many sibling list_* tools (list_tasks, list_contacts, list_invoices) beyond the resource name, so it falls short of a 5.

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 phrase "optionally for one contact" hints at a filtering scenario but never states when to use this tool versus alternatives, nor any prerequisites (e.g., that no filters returns everything, or how it relates to other project/task lookups). No when-not guidance is present.

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