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

This is the description's strongest contribution: it preempts the apparent conflict between the name 'add_client' and readOnlyHint=true by stating the tool 'opens nothing by itself' and returns instructions. It also discloses why the API route is unavailable (no public API, developer docs 'gone'), which explains the browser-automation path. It does not say how long or what shape the returned guide takes, but the annotations already carry the safety profile.

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 sentences, front-loaded with what the tool returns and followed by the handoff and the rationale. The final API sentence is tersely phrased ('its developer docs return "gone"') and slightly telegram-style, but it earns its place by justifying the browser route.

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, no-output-schema guide tool, the definition covers what it returns, what it does not do, and what to do next. The main residual gap is that it never says the guide is FitBudd-specific knowledge that should be preferred over improvising steps, but nothing essential to calling it correctly is missing.

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 tool takes zero parameters, so there is no schema semantics to add or compensate for; baseline applies. The description correctly implies input is unnecessary because the guide is static per app.

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 name/title read like a write action ('Add client'), but the description immediately reframes it: 'Returns how to do it in FitBudd step by step (screens, buttons, fields)'. That is a specific, distinguishable purpose — a procedural guide generator — not a mutation. It stops short of naming a sibling it could be confused with (e.g. cotlet_app_guide), so the differentiation is implied rather than stated.

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 sequence is clear: call this to get the step-by-step, then execute with 'the cotlet_browser_* tools in the user's FitBudd Cloud Browser'. The negative case is also covered — 'opens nothing by itself' tells the agent this will not perform the action. No explicit 'when not to use this instead of X' routing beyond the browser-tool handoff.

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