MetaMask Embedded Wallets (Web3Auth) MCP

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

Annotations declare readOnly/idempotent/openWorld, so the safety profile is covered. The description adds valuable implementation context: 'Tries Algolia, then llms.txt, then GitHub raw MDX as fallbacks,' revealing the resolution strategy and external dependencies consistent with openWorldHint.

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 with zero waste: purpose (sentence 1), usage guideline (sentence 2), behavioral implementation (sentence 3). Front-loaded with the core action and appropriately sized for the tool's complexity.

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 1 parameter, full annotations, and no output schema, the description adequately covers the tool's function, prerequisites (search_docs first), and fetch behavior. Lacks explicit return value description, but 'Fetch the full content' implies the output sufficiently for a read operation.

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% with a clear description and example for the 'url' parameter. The description reinforces this is for 'documentation page' URLs, but adds no syntax, format constraints, or semantic details beyond what the schema already provides. Baseline 3 is appropriate given schema completeness.

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 specific action ('Fetch the full content') and specific resource ('MetaMask Embedded Wallets documentation page'). Clearly distinguishes from sibling search_docs by implying this retrieves a specific page rather than searching.

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 states workflow: 'Use after search_docs to read the actual doc.' This provides clear sequencing guidance and distinguishes it from the search_docs sibling tool, indicating it requires a URL from search results rather than being a starting point.

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 cover read-only/idempotent safety (readOnlyHint/idempotentHint) and external dependency (openWorldHint). The description adds valuable behavioral context about the return value ('Returns all source files') and confirms the external GitHub source, aligning with openWorldHint. Does not mention rate limits or caching, but covers the essential behavioral traits.

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 well-structured sentences: purpose (fetch source), return value (all source files), and usage guideline (prefer over SDK). Zero redundancy, front-loaded with action verb, every sentence 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?

Despite no output schema, the description explains what gets returned ('all source files'). With 5 optional filter parameters and clear differentiation from siblings, the description provides sufficient context for invocation. Minor gap: could explicitly note that all parameters are optional filters, though this is inferable from schema.

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%, with all 5 parameters fully documented in the schema (name, chain, category, platform, auth_method). The description does not add parameter-specific semantics, but the schema carries the full burden appropriately. Baseline 3 applies.

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 specific verb 'Fetch' with clear resource 'complete source code of a Web3Auth integration example' and scope 'from GitHub'. It effectively distinguishes from siblings like get_sdk_reference and get_doc by specifying 'example' content.

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 states preference hierarchy: 'Examples are the PRIMARY reference for integration patterns — always prefer example code over raw SDK source'. This directly guides selection over sibling tool get_sdk_reference.

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 indicate read-only/idempotent behavior, while the description adds crucial context about data quality ('many SDK options are internal or legacy') and source provenance ('open-source Web3Auth SDK repos'). It explains what the agent will actually receive (constructor signatures, error types) without contradicting the safety annotations.

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 with zero waste: first establishes function, second gives constraints/warnings, third provides sibling alternative. Information is front-loaded and every clause earns its place. No redundant filler despite covering complex usage guidance.

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?

Comprehensive for a reference-fetching tool: it explains return values (compensating for missing output schema), warns about legacy data pitfalls, and differentiates from siblings. Minor gap: it does not mention cache behavior or failure modes (e.g., invalid platform), though openWorldHint implies external dependency.

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?

With 100% schema description coverage, the baseline is appropriately 3. The description mentions 'type definitions, interfaces, hooks' which semantically aligns with the 'focus' enum values, but does not add syntax details, validation rules, or examples beyond what the schema already provides.

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 opens with specific verbs ('Fetch') and resources ('SDK source code', 'type definitions, interfaces, hooks') from specific sources ('open-source Web3Auth SDK repos'). It clearly distinguishes from sibling tool get_example by stating 'Always use get_example first for integration patterns', making the scope 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?

Explicitly states when to use ('REFERENCE and DEBUGGING only', 'to verify exact type shapes') and when NOT to use ('Do NOT use this to discover features'). It names the specific alternative tool ('get_example') for the preferred workflow, providing clear decision criteria.

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 declare readOnly/idempotent/openWorld, so description adds valuable behavioral context: it specifies the external domain (builder.metamask.io), clarifies the dual-mode nature (search via query OR fetch specific thread via topic_id), and indicates content type (posts, discussions). No contradictions with annotations.

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 with zero waste: first defines scope and resource, second provides usage context, third explains parameter selection. Information is front-loaded and every clause earns its place. Appropriate length for the tool's complexity.

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 2-parameter search tool with comprehensive annotations covering safety profile, the description is complete. It covers purpose, usage context, parameter semantics, and data source. Absence of output schema is acceptable as the description indicates return content ('posts', 'full discussion').

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%, establishing baseline 3. Description elevates this by explaining the functional distinction between parameters: 'query to search' versus 'topic_id to read the full discussion.' This semantic mapping helps agents understand the mutually exclusive usage pattern beyond the raw schema definitions.

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?

Description clearly states the tool searches or fetches posts from the 'MetaMask Embedded Wallets community forum (builder.metamask.io)'. It uses specific verbs (search/fetch) and identifies the exact resource type (community posts), distinguishing it from siblings like search_docs or get_doc which handle official documentation.

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 states when to use: 'for troubleshooting real user issues, finding workarounds, and checking if an issue is known.' This differentiates community content from official documentation. Missing explicit 'when not to use' or direct sibling comparisons, though the domain specificity ('community forum') provides clear contextual boundaries.

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 declare readOnly/idempotent/openWorld hints. Description adds valuable return value disclosure ('doc page links with snippets and matching example projects') beyond annotations. No contradictions with safety hints. Does not disclose rate limits or pagination, but annotations cover core behavioral traits.

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 with zero waste: sentence 1 defines action/resource, sentence 2 specifies use cases, sentence 3 explains return values. Front-loaded with core functionality. Every sentence 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?

Comprehensive for a search tool: covers 4 well-documented parameters (via schema), explains return structure despite lacking output schema, and annotations cover safety profile. Minor gap: no mention of result ranking or pagination limits.

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% with detailed enums and examples (e.g., query parameter includes 'React custom auth' example). Description does not add parameter-specific semantics beyond schema, which is appropriate given complete schema coverage establishes baseline 3.

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?

Specific verb (Search) + exact resource (MetaMask Embedded Wallets/Web3Auth docs/examples) + scope (discovery/feature lookup). Distinguishes from sibling 'get_doc' and 'get_example' by emphasizing search/discovery functionality versus direct retrieval.

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?

Provides clear positive use cases ('SDK discovery, feature lookup, finding relevant examples') establishing when to use. Lacks explicit negative constraints or named alternatives (e.g., 'don't use for specific doc retrieval, use get_doc instead'), though the discovery vs. retrieval distinction is implied.

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