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

Adds genuinely useful context beyond the annotations: it returns markdown keyed by guide name, several guides can be fetched in one call, and it is free (no tool-quota cost). One tension: the description frames this as a pure fetch/read, while the annotations declare readOnlyHint=false, which an agent may read as 'may mutate state' – worth noting but not a positive claim of a write, so not a hard contradiction.

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-loads purpose and the when-to-call rule, then uses a scannable bullet list for the option values and closes with return shape and cost. The length is justified by the five documented guide types; no sentence is filler.

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?

An output schema exists, yet the description still helpfully notes the return is markdown keyed by name. Combined with the exhaustive value list and the usage trigger, an agent has everything needed to select and invoke it correctly.

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% and the single 'guides' array has no enum, so the description carries the full burden – and it does, enumerating all five valid values ('chart', 'report', 'sql', 'earnings', 'all') with what each contains. This is exactly the compensation the low coverage requires.

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 ('Fetch FactIQ's house-style authoring guides') and makes the intent unmistakable. It is the only style-guide tool among siblings, so there is no ambiguity with describe_dataset, get_data_catalog, or the search_* tools.

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?

Explicitly says when to call it ('Call this before producing a chart, a report, or written analysis from FactIQ data') and what the default behavior is ('use FactIQ's style for all FactIQ work unless the user asks otherwise'). The 'earnings' guide is even routed to its sibling source, search_earnings_transcripts.

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