Defici Marketplace MCP Server

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 discloses that contact details are excluded, that all listing statuses (active/sold/expired) return results, and preemptively explains the currency_note field. This is notable behavioral disclosure for a read-only fetch tool. Could have mentioned return format, but this is a fetch-by-id utility where behavior is fairly obvious.

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 — three sentences covering purpose, status scope, and the currency_note caveat. It's front-loaded with the verb+resource and each sentence earns its place. Slightly longer than necessary but every statement adds value, particularly the currency_note disclosure which prevents agent confusion.

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 single-parameter fetch tool with 100% schema coverage, the description is quite complete. It covers result conditions, an important exclusion (contact details), and preemptively explains a surprising field (currency_note). No output schema exists, so describing the currency_note field compensates partially for that gap. The description is adequate for agent selection and invocation.

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% (the single 'id' parameter is described as 'Listing UUID (e.g. from search_listings results)'). The description reinforces this by stating UUID usage but doesn't add much beyond the schema. Baseline 3 applies since the schema handles the parameter documentation well.

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 clearly states the verb ('Fetch'), the resource ('full details for a single listing'), and identifies it by 'UUID'. It distinguishes from siblings: search_listings is for searching, while this is a single-listing detail fetch. The marketing of scope (active/sold/expired) adds clarity.

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 specifies when to use it (fetching full details for a single listing by UUID), and implicitly distinguishes from search_listings (which returns lists/results). It clearly states contact details are NOT returned, directing users to the web interface instead — an explicit negative scope statement. No explicit naming of alternatives, but sibling differentiation is implied via the UUID-single-listing nature.

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 full behavioral burden. It discloses that numbers are read live at request time and that fields are omitted rather than guessed or zero-filled (CBR41), which is valuable, non-obvious behavior that helps agents trust the output.

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 with 'What Defici is and its current live scale,' then quickly specifies what's included and the handling of missing data. Every sentence serves a purpose with no fluff or repetition.

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 zero parameters and no output schema, the description adequately covers the tool's purpose, content, and edge-case behavior (omitting unbacked fields). It is self-contained sufficient for an agent deciding whether and how to invoke the 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?

The tool has zero parameters, so the baseline score of 4 applies. The schema is empty, and the description makes it clear there's nothing to configure, so no further parameter semantics are needed.

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 clearly states the tool provides an overview of Defici's platform identity and live scale, contrasting it with 'a listings search result' and enumerating specific content: markets, categories, enabled modules, and scale metrics. This distinguishes it from sibling tools like search_listings and get_listing.

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 explicitly advises calling this tool first for agents unfamiliar with Defici beyond search_listings, giving a concrete scenario. It also implicitly says what it's not for ('not a listings search result'), though it doesn't name alternative tools or provide explicit when-not-to-use cases for other siblings.

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 are provided, so the description carries the full behavioral burden. While it doesn't mention safety (this is presumably a read-only fetch tool), it does disclose the output fields (id, country, currency, languages), which gives the agent expectations about what the response will contain. Given the low risk nature (a list of static regions) and 0 parameters, the disclosure is reasonably complete, though it could note that no input is required.

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 wasted words. The first sentence states the purpose and output fields; the second provides the actionable usage tip connecting to search_listings. This is textbook conciseness with front-loaded purpose.

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 zero-parameter, no-output-schema tool that returns static market data, the description is fully adequate. It states what is returned, the fields included, and how to use the result. There are no nesting complexities, required parameters, or side-effects to disclose. The tool is simple enough that this description is genuinely complete.

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?

The tool has zero parameters, so the baseline is 4 per the rubric. The description appropriately references the returned 'region id' as a consumable value, which indirectly gives the agent context about the meaningful output. With no parameters, there's little parameter semantics to add.

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 precisely what the tool does: 'Return all supported market regions' with their specific fields (id, country, currency, languages). It clearly distinguishes itself from siblings (get_listing, list_categories, search_listings) by being the market-lookup tool. The verb 'Return' plus resource 'market regions' is specific and 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 description explicitly tells when to use it and how: 'Use the region id as the market argument in search_listings.' This is an explicit cross-reference to a sibling tool, providing clear guidance on the tool's role in a workflow. This is exemplary usage guidance since it connects this tool's output to consumption by another tool.

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 burden of behavioral disclosure. It helpful states that no price figure is returned, covers two independent tiers, and lists only live capabilities. It does not address read-only behavior, output shape, or potential errors, but it does provide meaningful behavioral context beyond the tool name.

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 with what the tool returns, followed by important caveats. Each sentence contributes useful information, though the caveats could be tightened slightly.

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 zero-parameter informational tool with no output schema, this description gives sufficient context: what the tool covers, what it deliberately excludes, and how tiers are scoped. It does not explain the exact return structure, but the high-level behavior is clear enough for correct invocation.

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?

The tool has zero parameters, so the schema provides nothing to clarify. The description appropriately explains what content the tool returns and what it intentionally omits, which is the main semantic information an agent needs.

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 clearly states the tool returns capability tiers for Defici and what each tier unlocks, distinguishing it from price-related or platform-overview tools. It lacks an explicit verb like 'returns' or 'gets', but 'available' and the detailed scope make the purpose clear.

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 this tool should be used when an agent needs to know current capability tiers, plan limits, or partner-tier features. It does not explicitly state when not to use it or mention alternatives among the siblings, so usage guidance is inferred rather than explicit.

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 are provided, so the description carries the burden. It discloses the tool returns a taxonomy and that the ids are used in search_listings. It doesn't describe return format, ordering, or whether this varies by region, but with zero parameters and a simple read operation, the behavioral disclosure is reasonably adequate relative to complexity.

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 waste. Every word earns its place: states the resource, names the platform, and connects the output to a downstream tool. Perfectly front-loaded with the core purpose.

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 parameterless tool with no output schema, the description is appropriately complete. It explains what's returned (category taxonomy), and why the agent should call it (to feed category ids into search_listings). A richer description would describe the shape of the taxonomy, but given the tool's simplicity, this is adequate.

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?

The tool has 0 parameters, so the baseline is 4. There are no parameter semantics to elaborate, and the description appropriately focuses on the output/usage rather than parameters. Nothing more is needed here.

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 clearly states the tool returns the complete category taxonomy for Defici.com, with a specific resource ('category taxonomy'). It also distinguishes the purpose by explaining the relationship to search_listings via the category id values. This is a specific verb-resource pairing with clear 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?

The description explicitly tells the agent when to use this tool: to obtain category id values that serve as the category argument in search_listings. It provides clear usage context by connecting to a sibling tool. It doesn't explicitly state exclusions/when-not-to-use, but the connection to search_listings effectively establishes the workflow context.

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 provided, the description carries the full burden of behavioral disclosure. It clearly states that the tool reads live from the module registry (so results are always reachable), and it explains the structure of each entry (manifest URL) and what to do with it. This goes beyond a typical list tool and provides meaningful transparency.

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 three focused sentences, front-loaded with the core purpose, followed by the live-read guarantee and the manifest URL instruction. Every sentence adds unique value, with no redundancy or 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?

Despite no output schema and no annotations, the description covers the purpose, the live source (module registry), the guarantee of reachability, and the actionable next step (calling the manifest URL for details). For a zero-parameter, low-complexity list tool, this is complete and self-sufficient.

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?

The tool has zero parameters, and the schema coverage is 100% with an empty schema. The description does not need to explain parameter semantics, and as a baseline for no parameters, a score of 4 is appropriate. It adds useful context about the result entries but not parameter details, which are unnecessary here.

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 uses a specific verb ('List') and clearly identifies the resource ('every module currently enabled on Defici'), while explicitly distinguishing itself from 'core listings' and naming examples like contests, market search, and agent forum. This makes it easy to differentiate from sibling tools such as get_listing and search_listings.

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 provides clear context on when to use this tool (to discover currently enabled modules) and implies it is not for core listings. However, it does not explicitly name alternative tools or state when not to use it, so it falls short of full explicit guidance.

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 are provided, so the description carries full burden. It excellently discloses the critical caveat that prices are raw numbers with no confirmed currency unit, explicitly warns against treating price as a specific denomination or comparing values, and even explains the currency_note field structure in results. This is valuable behavioral context beyond what the schema provides.

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 front-loaded with purpose and reasonably compact. It packs significant value into a few sentences, with the critical currency caveat getting prominent placement. Slightly redundant with the price_max/price_min parameter descriptions that repeat the currency warning, but overall efficient.

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 no annotations and no output schema, the description carries substantial burden and handles it well. For an 8-param discovery tool with pagination and cross-market nuance, it covers the critical behavioral caveats (currency ambiguity), return structure (paginated, currency_note field), and safety profile (read-only). The mix of data-quality disclosure plus result-shape guidance is strong for a complex 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 description coverage is 100%, so the baseline is 3. The description adds contextual meaning for price parameters (warning currency issues) and references get_regions and list_categories for market/category valid values, which complements the schema. However, most parameter semantics are already well-covered by the input schema descriptions themselves.

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 clearly states 'Search active listings on Defici.com global marketplace' with a specific verb and resource, and distinguishes itself from siblings by noting it returns paginated results and does not include contact details. It's distinct from get_listing (single-item fetch), get_regions, and list_categories.

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 clearly brands this as a read-only discovery tool and notes that contact details are not included, which helps agents know when NOT to use it (e.g., for contacting sellers). However, it doesn't explicitly name sibling alternatives like get_listing for a single result, or explicitly state when to choose it over other tools.

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