Fitness Starter – hand-picked gift ideas

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

No annotations are provided, so the description carries the full burden. It does disclose that an editToken is required, hinting at write authorization, but says nothing about duplicate handling, whether the tool resolves the product metadata server-side, failure modes, or what is returned.

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 short, front-loaded sentences with no filler. The second sentence partly restates the required array, but it is cheap and orients the agent quickly.

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?

A 12-parameter mutation tool with no annotations and no output schema needs far more coverage than one sentence. The identification strategy and editToken's meaning are the crux, and neither is addressed.

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 only 33% across 12 parameters. The description mentions id, editToken, marketplace, and locale — but the hardest ambiguity, how url vs asin vs searchKeywords vs name/title are used to identify the item, is entirely unexplained in both schema and description.

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 with scope: 'Add a gear item to an existing pack.' The 'existing pack' qualifier implicitly distinguishes it from create_pack and create_and_fill, though those siblings are never named.

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 'existing pack' implies this is for packs that already exist, which nudges the agent away from create_pack. But there is no explicit when-to-use/when-not guidance and no mention of browse_catalog, search_gear, or resolve_product as upstream alternatives for finding the item to add.

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?

With no annotations, the description carries the full burden. It discloses important marketplace resolution and fallback behavior, but omits default limit/ordering, auth requirements, and other operational details for an eight-parameter listing tool.

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?

The description is compact and front-loaded, starting with the core list operation before marketplace mapping. The marketplace/tag details are dense but directly useful, with little wasted text.

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?

Given eight parameters, no annotations, no output schema, and low schema coverage, the description should do more. It explains marketplace selection and filters but leaves limit behavior and return ordering/pagination unstated.

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 38%, so the description must compensate. It covers q, goal, level, budgetBand, and marketplace resolution, but leaves limit unexplained and does not clarify enum meanings.

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: "List hand-picked catalog products with /dp/ buy links." It also clarifies the two marketplace catalogs, but does not explicitly differentiate itself from siblings such as search_gear.

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 description implies usage through filters and marketplace behavior, but never states when to use this tool instead of search_gear or resolve_product. No exclusions or alternatives are given.

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?

No annotations exist, so the description carries the full burden. It does disclose return values (ownerUrl, shopUrl, editToken) and the marketplace default/fallback chain, which is real added context. But it omits whether creation requires auth, whether the returned editToken is a sensitive credential, and what happens on partial fill failure — significant gaps for a mutating tool with zero annotation coverage.

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 tight sentences, front-loaded with the action and the returns. The marketplace sentence duplicates schema text almost verbatim, which is wasted space given the real gaps elsewhere.

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?

Ten optional parameters, no required fields, no output schema, and no annotations — this tool needs more guidance than most. The description covers the response keys and locale defaulting but says nothing about how the item-selection parameters combine or what a minimal valid call looks like, which is exactly what an agent needs here.

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 only 30% across 10 parameters. The description elaborates only on marketplace (which the schema already documents at length), while the parameters that actually drive the 'fill' behavior — itemAsins, itemQueries, itemKeywords, goal, level, budgetBand — get no explanation of precedence or intent. An agent cannot tell from the description whether it must supply ASINs, queries, or keywords to get a useful pack.

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: 'create a pre-filled gift pack', and names the sibling create_pack. However 'same as create_pack' is ambiguous — it gestures at a sibling without clarifying what the 'and_fill' half adds (presumably items are selected automatically from the item* params), so the differentiation is partial.

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 leading 'One call:' implies this is the shortcut versus create_pack followed by add_item, which is an implied usage signal. There is no explicit 'use this when…, use create_pack when…' routing, and no statement of preconditions or when the fill step can fail.

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?

With no annotations, the description does carry the burden, and it usefully discloses return fields including the sensitive editToken plus the marketplace fallback chain (country → Accept-Language → amazon.se). It omits side effects, whether the pack is persisted/editable after creation, and any auth or idempotency notes.

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 and short, with the purpose and outputs stated first. The trailing clause 'optional (en-US → amazon.com, otherwise amazon.se)' is a compressed fragment that is hard to parse out of context and duplicates schema text rather than adding clarity.

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 10-parameter creation tool with no annotations and no output schema, the description covers only marketplace resolution; how goal/level/budgetBand and the three item-* arrays combine to pre-fill a pack is left entirely implicit.

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 only 30%: goal, level, budgetBand, athleteName, itemAsins, itemQueries and itemKeywords are undocumented in both schema and description. The description expands only on marketplace (largely repeating the schema's own text) and hints at locale, leaving the interaction among the seven bulk parameters unexplained.

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?

"Create a gear pack (optionally pre-filled)" names a specific verb and resource, and the return-value list clarifies scope. It does not, however, distinguish this from the sibling create_and_fill, leaving the boundary between 'optionally pre-filled' and 'fill' ambiguous.

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 sentence tells the agent when to choose this over create_and_fill or add_item; the marketplace/locale text is parameter behavior, not usage guidance. The only implied guidance is the 'optionally pre-filled' hint, which the agent must infer.

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?

With no annotations, the description carries the full burden; it does disclose the return shape (buyUrl + trackingTag) and reveals affiliate-tag behavior (tag sw-fitness-20 in the schema text), which is meaningful context. However it says nothing about failure modes (unresolvable ASIN/keywords), whether tracking is always applied, or which storefront wins for keyword-only input.

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 dense sentences, front-loaded with the core verb and input forms, followed by the storefront defaulting rule. No filler and nothing restated from the tool name.

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?

No annotations and no output schema, so the description must do more work; it names the return fields and the storefront resolution logic, which covers the happy path. It falls short on the two undocumented enum parameters and on what happens when resolution fails, leaving real gaps for an 8-parameter tool.

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 only 38%, so the description must compensate. It partially covers url/asin/keywords by naming them as accepted inputs and explains marketplace/country/locale precedence, but the 'goal' (run/lift/yoga) and 'level' (starter/building/serious) enums are left completely unexplained in both schema and description — an agent cannot infer their meaning or whether they are required for keyword resolution.

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?

Uses a specific verb ("Resolve") with three named input forms (ASIN, Amazon URL, keywords) and a concrete output (buyUrl + trackingTag). An agent can tell this is a resolution/link-building tool rather than a search tool, though it never names the sibling tools (search_gear, browse_catalog) it must be distinguished from.

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 marketplace defaulting chain (en-US → amazon.com, else amazon.se) gives useful invocation context, but there is no explicit statement of when to use this versus search_gear or browse_catalog, and no preconditions or exclusions. Usage is implied rather than guided.

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?

No annotations exist, so the description carries the full burden; it does disclose the return shape and the marketplace/locale defaulting chain, which is genuinely useful. However, it never says the operation is read-only/safe, that all parameters are optional, or how many results limit produces, leaving notable behavioral gaps.

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 tightly packed sentences with the core capability front-loaded and the regional configuration second. Some of the trailing marketplace/locale detail duplicates the schema, which is mild redundancy rather than bloat.

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 8 parameters, no annotations, and no output schema, the description should explain more of the filtering model. It is silent on what goal, level, and budgetBand actually do to the results and on the limit default's effect, leaving an agent unable to reason about half the inputs.

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 75%, so most parameters are already documented, and the description's explanation of the marketplace/locale precedence largely restates the marketplace and locale schema descriptions. It adds the 'US shoppers' heuristic but says nothing about goal, level, or budgetBand, whose schema entries are enum titles with little or no explanation.

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 and resource ('Search fitness gear') and goes further by naming the return composition: hand-picked /dp/ matches plus English or Swedish search links. It never explicitly contrasts itself with browse_catalog or resolve_product, so an agent must infer the boundary from the /dp/ catalog language.

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 one concrete usage cue, 'Pass marketplace=amazon.com for US shoppers', which is really a parameter instruction rather than a when-to-use rule. There is no statement of when to prefer this over browse_catalog or resolve_product, and no exclusions.

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