XipFax

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so safety is covered. The description adds genuine provenance context — the list is XipFax's, sourced from the IRS's own pages — which is useful for trust, but it says nothing about what happens when no office matches or how results are shaped.

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 short sentences, front-loaded with the core action and followed by input guidance in the order the parameters are used. No filler, though the imperative phrasing ('Give the form…') is slightly indirect compared to simply stating the input format.

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 an output schema present, return values need no explanation, and both parameters are fully documented in the schema plus the description's conditional rule. The only gap is the no-match case, which an agent calling this tool would benefit from knowing.

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 a 3 is the baseline. The description goes beyond it by clarifying that the form should be given by name or number alone, and by stating the conditional rule that place is only needed where the IRS publishes per-state numbers — a relationship between the two parameters the schema does not encode.

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 names a specific verb and resource — finding the fax number of the IRS office that handles a given form or notice — and scopes the data source ('XipFax's list of offices, read from the IRS's own pages'). It does not explicitly contrast with the siblings quote_fax and send_fax_link, but the purpose is distinct enough that confusion is unlikely.

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?

Usage context is implied ('give the form or the notice by its name or number alone'), and the conditional rule for the place parameter is stated ('Where the IRS gives a number for each state, give the place too'). There is no explicit when-not-to-use guidance and no named alternative for related tasks such as quoting or sending a fax.

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

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

Annotations already declare readOnly, idempotent, closed-world and non-destructive behavior, so the safety profile is covered. The description adds that pricing comes from XipFax's price list and excludes plan pricing, but says nothing about currency, tax, or whether the quote is binding.

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?

A single efficient sentence with no filler. The phrasing is slightly indirect ('The price of sending...' rather than 'Quotes the price...'), but it is front-loaded and compact.

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 an output schema present, return values need no explanation, and annotations cover the safety profile. For this simple one-parameter quote tool the description supplies enough context, though noting currency or that the quote targets non-plan pricing only would close the remaining gap.

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 coverage is 100% and the single 'pages' parameter is already documented with its 1–250 range. The description only restates the page-count concept, adding no format or constraint detail beyond the schema.

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 specifies the resource (one fax, N pages, XipFax, no plan) and that it returns a price from the price list, which distinguishes it from send_fax_link and find_fax_number. It states the returned value rather than using a direct verb like 'calculate' or 'quote', but the intent is unambiguous.

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 phrase 'without a plan' implies a scope condition, but there is no explicit when-to-use or when-not-to-use guidance and no mention of alternatives for plan-based pricing. Usage is inferable from context rather than stated.

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

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

Well beyond the annotations, the description discloses that this tool does not send anything itself — the recipient of the link adds pages, signs in, and pays in a browser. That human-handoff behavior is the single most important thing an agent needs to know and is consistent with readOnlyHint/idempotentHint. The downstream login and payment expectations are also surfaced, which annotations cannot express.

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 sentences, front-loaded with the core output and followed by the input alternatives and the downstream step. No filler, and the optional detail lives in the second sentence where it belongs.

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, so the link's return value needs no explanation. For a two-optional-parameter URL generator with full annotation coverage, the description supplies the calling convention, the input alternatives, the eligibility constraint, and the human handoff — nothing an agent needs 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?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning: it establishes the two inputs as alternatives ('an office ... or a fax number'), a mutual exclusivity the schema does not encode, and it constrains fax_number to the US, its territories, or Canada. The office_id origin from find_fax_number also tells the agent where the value comes from.

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 names a concrete output (a link that opens XipFax's send screen pre-filled with a fax number) rather than restating the title. An agent can tell this generates a handoff URL, not a fax send. It does not explicitly contrast itself with the sibling quote_fax, which is the one missing clarity element.

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?

It gives clear context for invoking: pass an office_id sourced from find_fax_number, or a raw US/territory/Canada fax number, and the human completes the send. That is actionable routing guidance plus a geographic eligibility rule. It stops short of stating when to prefer this over quote_fax (e.g., pricing vs. actual sending).

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