Worth

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

Annotations already cover readOnly, idempotent, non-destructive, open-world, so the safety profile is settled. The description adds a real behavioral trait: passing -1 causes an internal pricing step before comparison, which is not derivable from annotations or schema alone.

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 the usage trigger, then the return, then parameter guidance. No repetition of the title or wasted words.

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 return shape needn't be detailed, and the description covers when to use and how to supply the numeric inputs. Minor gap: no mention of how grade/category/condition influence the comparison, though their schema descriptions carry that.

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 explains the semantics of the -1 sentinel and the provenance of estimate_low/estimate_high from price_item, which the schema only hints at. It leaves grade/category/condition to the schema, which is reasonable.

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 (compare new, used, resale) and the exact question it answers. It also distinguishes itself from the sibling price_item by explaining how estimates flow between them.

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 explicit trigger conditions (user asks whether to buy new or used, or what they could sell for) and a clear branch: pass price_item's estimate_low/high when available, otherwise pass -1 and Worth prices the title first. Routing to the sibling is unambiguous.

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 readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds the return contents (estimate, new/used ranges, confidence), but that is largely duplicated by the existing output schema, and it says nothing about failure modes, auth needs or rate limits.

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, zero filler: usage trigger and input modes first, routing exclusions second. Well front-loaded and every clause 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?

With an output schema present, the description needn't restate return values, and with annotations carrying the safety profile, the definition covers what an agent needs to select and call the tool. Input modes, scope, and sibling routing are all present.

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% and each of the six parameters is documented in-schema, so the baseline is 3. The description's 'photo or a name' phrasing loosely maps to image_url/title/image_base64 and the optional nature of inputs, but adds no format or precedence 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?

States a specific verb+resource (price an item) and the input modes it accepts (photo or name) in the first sentence. It immediately distinguishes itself from compare_prices and where_to_buy_or_sell by naming both as out of scope.

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 an explicit triggering condition (user wants to know what one item is worth, with a photo or name) plus explicit exclusions with the correct alternative for each ('weigh new against used (compare_prices)', 'list stores (where_to_buy_or_sell)'). No inference required to route between the three tools.

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 cover safety (readOnlyHint, destructiveHint=false, idempotentHint, openWorldHint), so the bar is lower. The description adds real value by disclosing what comes back ('Worth tracking links') and a hard behavioral rule not to fabricate retailer URLs, which an agent would otherwise likely do.

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 when-to-use trigger followed by what it returns and the anti-hallucination rule. Every sentence earns its place with no 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, so return values need not be re-explained, and annotations cover the safety profile. The description supplies the trigger condition and the critical URL-fabrication constraint, though it omits any mention of result quantity, ranking, or geographic scope for the `place` parameter.

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 all four parameters (place, title, intent, category) are already documented in the schema. The description's mention of buy new/buy used/sell loosely maps to the intent enum but adds no syntax, format, or constraint detail beyond the schema, making the baseline 3 correct.

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 states a specific verb+resource: it returns a store or marketplace link for buying new, buying used, or selling. This is clearly distinct from price-oriented siblings like compare_prices and price_item, though the description never names those siblings explicitly to sharpen the distinction.

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?

'Use when the user wants a store or a marketplace link to buy new, buy used, or sell' gives a clear triggering condition, and 'Do not invent retailer URLs; use only the links in the result' is a concrete usage constraint. It does not state when to prefer this over compare_prices or price_item, 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.