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 'inspect' is consistent with that, so no contradiction. The description adds nothing beyond it: no indication of whether it reports errors versus warnings, whether the 250k character cap truncates input, or what a diagnosis result looks like, and there is no output schema to cover the gap.

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?

It is a single front-loaded sentence with no waste, which is structurally sound. The tradeoff is that the terseness crosses into under-specification, and 'for free' is ambiguous filler (no cost? non-destructive?) rather than informative content.

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 annotations beyond readOnlyHint, no output schema, and zero schema descriptions, the description is the only substantive documentation channel and it supplies almost nothing. An agent cannot tell what a diagnosis returns or how to use filename.

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 0% for both parameters, so the description must carry the load and largely fails. 'iCalendar text' loosely maps to calendar_text, but the filename parameter and the 250000 maxLength constraint are neither explained nor hinted at.

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 verb 'inspect' and resource 'iCalendar text' give a workable purpose, and the sibling family (diagnose_csv, diagnose_srt, repair_ics) implies format-specific checking versus repair. But 'inspect ... for free' never says what is actually checked (syntax? RFC 5545 compliance? warnings?) or what the agent gets back, so the purpose stays vague.

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?

No when-to-use guidance and no mention of the obvious alternative repair_ics, which shares the same domain. The agent must infer on its own that this is for read-only validation rather than fixing a calendar.

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