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

With no annotations and no output schema, the description carries the full burden. It usefully discloses the auth profile ('Needs no credential') and scope ('one page'), which an agent cannot get from the empty schema. Beyond that it says nothing about the return format or structure, so it is only partially transparent.

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?

Front-loaded with the core statement, then two tight sentences covering auth requirements and the trigger for reading it. The bolded credential note is well placed and every sentence earns its place.

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 informational tool with no output schema, the description covers purpose, auth profile, and usage trigger adequately. It could say a bit more about what the page actually returns, but nothing critical for invoking the tool 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 parameter semantics to add and the baseline of 4 applies. Schema coverage is nominally 100% (vacuous), and no meaningful param detail could be provided.

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 resource and scope: an overview of the platform's capabilities and limits, plus the topic areas it covers (VAT, payroll, reconciliation, AI accountant). The purpose is clear, but it does not distinguish itself from closely related meta-siblings such as zeno_info, describe_operations, or onboarding_guide, leaving the agent to guess which overview-named tool to pick.

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?

Gives a concrete trigger condition — 'Read this before telling a user that Zeno cannot do something' — which is a genuinely useful when-to-use cue. It offers no exclusions or explicit comparison to the other informational siblings (zeno_info, describe_operations), so it stops short of full alternative routing.

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