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

The annotations already indicate readOnly/openWorld/not destructive, and the description adds meaningful behavioral context: the tool is one round of an iterative workflow, returns gaps with suggested follow-up queries, and should be concatenated into a cited synthesis. This gives the agent useful expectations beyond the annotation flags.

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 two sentences, front-loaded with the core capability, and contains no filler. The iterative call pattern and final synthesis are stated economically and clearly.

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?

The description captures the essential workflow: perform one research round, follow the suggested follow-ups, stop when gaps are empty, then synthesize with citations. Since an output schema exists, return-value detail is not required. The main gap is the poor explanation of the parameter semantics, but overall the high-level usage context is sufficiently 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?

Schema description coverage is very low (17%), so the description must compensate, but it only vaguely refers to 'suggested_queries' without explicitly mapping it to the 'queries' parameter. The meaning of 'layer', 'recency', 'round', and 'max_sources' is left entirely to the schema, which is insufficient given the low coverage.

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 it performs 'one research round' combining 'complex fused search + coverage analysis + gaps + suggested follow-up queries.' This is a specific multi-phase verb-resource description that also distinguishes the tool from sibling tools like fetch_page and x_search by emphasizing iterative research coverage.

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 explicit usage guidance: 'Call repeatedly with suggested_queries until gaps is empty, then synthesize with citations.' This clearly explains the iteration and termination conditions. However, it does not explicitly compare against sibling tools or state when not to use it.

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 indicate readOnlyHint=true and destructiveHint=false. The description adds behavioral context: use of Jina Reader with a local HTML fallback (indicating reliability strategy) and focus filtering for token savings. No contradictions.

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: first states the core function and method, second adds the optional focus feature. No redundant or wasted content. Front-loaded effectively.

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 low complexity (2 params), rich schema descriptions, annotations, and an output schema, the description covers the main behavior and the focus filter. It could mention error handling or timeout but is sufficient for a simple fetch 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%, with both parameters already well-described ('http(s) URL to fetch', 'Keep paragraphs matching these terms (~90% token savings)'). The description only echoes 'Use focus to filter paragraphs', adding no new meaning.

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 'Fetch readable page text via Jina Reader with local HTML fallback', which is a specific verb+resource. It distinguishes from sibling search tools (e.g., fused_search, deep_research) by targeting a single URL rather than performing searches.

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 explicit when-to-use or alternatives are provided. However, the description implies usage for fetching content from a specific URL, and sibling tool names (search tools) suggest the context. Guidance is implied but not 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?

Annotations already indicate read-only behavior (readOnlyHint: true). The description adds context about URL dedupe, cross-ranking, and key requirements, which are behaviors not fully covered by annotations. This enriches transparency beyond the annotation baseline.

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 exceptionally concise—two sentences—and well-structured. It avoids redundancy and directly conveys essential information without extraneous words, making it easy to parse.

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 the schema provides some parameter descriptions and an output schema is present, the description's lack of return format or further behavioral details is acceptable. It supplies sufficient context for a search tool, but could be slightly more thorough regarding result handling or limitations.

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 description does not explain any parameter semantics. Schema coverage is only 44% (query and max_results have descriptions), leaving many parameters (layer, engines, queries, recency, complexity, exclude_domains, include_domains) undocumented. Since the description adds no parameter details, it fails to compensate for incomplete 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 clearly states the tool's function: 'Multi-engine parallel search with URL dedupe and cross-ranking.' It specifies the action (search), the resource (multi-engine), and distinguishes from a built-in WebSearch, meeting the bar for specificity and differentiation.

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 explicit guidance on when to use this tool: 'Prefer over built-in WebSearch for version-sensitive facts, APIs, comparisons, and research.' It also differentiates free vs. API layers, offering clear usage context without ambiguity.

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?

The annotations already indicate this is not read-only and not destructive; the description adds meaningful context by explaining what switching to 'free' vs 'api' changes about the underlying engine composition. It does not detail side effects or persistence, but for a simple configuration switch, the disclosed behavior is sufficient. No contradiction 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?

The description is extremely compact, with the core action front-loaded in the first sentence and the mode meanings packed into the second. Every clause adds value, and there is no redundant repetition of the title or schema.

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 one-parameter optional configuration tool with no output schema, the description covers the main decision space well. The only notable gap is 'show' behavior not being described in the mode definitions, but the overall tool is simple enough that this does not severely compromise completeness.

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 0% schema description coverage, the description carries the burden of explaining parameters. It successfully explains two of the three enum values ('free' and 'api') with concrete engine lists. The 'show' value is only implied by the opening verb and lacks explicit detail about what it displays or returns.

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 a specific verb+resource combination, 'Switch or show search layer,' which clearly identifies the action and target. It also distinguishes this tool from the sibling search tools by focusing on layer configuration rather than executing searches, and the mode definitions reinforce the purpose.

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 gives clear context for when to choose each layer value: 'free' for keyless engines only, 'api' for adding keyed engines, and 'show' to inspect the current layer. It does not explicitly state when not to use the tool or name alternatives, but the mode explanations provide practical selection 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?

Annotations already declare readOnlyHint=true and destructiveHint=false, so the behavioral profile is clear. The description adds useful context about what diagnostics are included but does not mention rate limits, permissions, or other traits beyond the 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?

The description is a single, concise line with no wasted words. It is front-loaded with 'Diagnostics:' to immediately signal 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?

Given zero parameters, an output schema, and clear sibling tool names (all search functions), the description is complete for an agent to understand the tool's purpose and when to use it.

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?

There are zero parameters, so baseline is 4. The description adds value by listing the diagnostic categories, which is the only source of information about what the tool returns.

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 indicates this is a diagnostics tool for search statistics, listing specific categories (cache hits/misses, tier counts, etc.). It distinguishes itself from sibling tools like fused_search and deep_research, which are search functions.

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 implicitly suggests use for diagnostics, but does not explicitly state when to use this tool versus alternatives (e.g., 'use this to check cache health, not for searching'). No exclusion criteria or sibling differentiation is provided.

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=true, openWorldHint=true, and destructiveHint=false. The description adds valuable context: it works without credentials (multi-engine + oEmbed fallback) and mentions the official API path. This goes beyond what annotations provide, though it could detail fallback behavior more.

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 two sentences, front-loaded with the main capability. It is concise without wasted words, but could be slightly more structured (e.g., separating search types from credential notes).

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 having an output schema, the description does not explain how different search types require specific parameters (e.g., thread needs post_id, user needs username). It lacks completeness for a tool with 7 parameters and multiple search modes.

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 29% (only to_date and from_date have descriptions). The description does not explain any parameters, such as how query, post_id, username, or max_results relate to the search types. Given low coverage, the description should compensate but does not.

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 performs real-time X/Twitter search with four specific types: keyword, semantic, user profile, or thread. It also mentions credential modes. However, it does not explicitly differentiate from sibling tools like fused_search or search_layer, which could be helpful for selection.

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 mentions that the tool works without credentials but has an official path via grok login or XAI_API_KEY. This provides some context on authentication, but it does not give any guidance on when to use this tool versus sibling tools or what prerequisites are needed for each search type.

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