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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds the upstream endpoint mapping (GET /api/v1/projects) and the field shape of the response, which are genuinely useful. However, it says nothing about pagination behavior or result limits beyond what the schema parameters imply.

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 short sentences, front-loaded with the returned field list and trailing with the API endpoint, with no filler. Minor redundancy is that the opening phrase restates the title 'List projects' verbatim, but the sentence remains dense and well ordered.

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?

With no output schema, the description partially compensates by naming the returned fields, and the schema fully documents all filter/pagination parameters. The read-only nature is covered by annotations, so an agent has nearly everything needed; only pagination defaults and cross-tool routing are absent.

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 all seven parameters (page, sort, filter, number, status, per_page, client_id) are already fully documented including formats and examples. The description adds no parameter meaning of its own, 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?

The description states a specific verb and resource ('List projects') and enumerates the payload fields returned (client, budgeted hours, task rate, current hours, due date), so an agent knows exactly what this tool produces. It is clearly distinguishable from siblings like invoiceninja_list_tasks or invoiceninja_list_clients by resource name, but it never explicitly contrasts itself with those alternatives.

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 when-to-use or when-not-to-use guidance, no mention of prerequisites such as needing a client_id, and no routing to siblings for related lookups (e.g. list_tasks for a project's tasks). Usage is only implied by the tool name and the verb 'List'.

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