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

Warns about attacker-authored content and describes how different MIME types are handled (inline images, untrusted blocks, signed links, file paths). No contradictory annotations exist, and the safety context is valuable.

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?

Every sentence adds meaningful detail—behavior, safety, and return formats. No fluff or redundancy; length is justified by the security context.

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?

Covers return behavior and security, and references the prerequisite tool 'show'. Missing error cases or fallback instructions, but for a targeted attachment fetch, the essential context is 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?

The 'part' parameter is explained via reference to 'show's output', but the 'id' parameter is not described at all. Since half the required parameters lack semantic guidance, the score is below the baseline.

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?

Clearly states the verb 'Return' and the resource 'attachment or MIME part of a message'. Unambiguous and distinguishes from sibling tools that list or show 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?

Provides a precondition by referencing 'show's output' for the part number, but does not explicitly contrast with sibling tools like 'text' or 'files'. Still, the purpose is specific enough for an agent to select 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?

No annotations are present, and the description does not disclose whether the operation is read-only, has side effects, or requires specific permissions. Counting is typically non-destructive, but this is not stated, leaving uncertainty.

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 very brief and directly to the point. It lacks depth, but the structure is clean and not verbose, earning a middle-high score for conciseness.

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 tool lacks an output schema and does not describe the return format or potential errors. The minimal description is insufficient for an agent to understand what the tool returns or how to handle edge cases.

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 input schema lists three parameters (query, account, include_excluded) but provides no descriptions. The description does not explain their semantics, types, or expected values, so the agent has to infer meaning from names alone.

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 action is 'Count the messages matching a query,' but it does not specify the context (e.g., which message store or type) or how it differs from related tools like search. It is somewhat generic.

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 guidance is provided on when to use this tool versus alternatives. There is no mention of search, show, or other sibling tools, leaving the agent without direction on selection 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?

With no annotations, the description is the sole source of behavioral information. It states only that the tool returns file paths, but does not disclose potential side effects, permission requirements, error behavior, or whether the operation is read-only. This lack of transparency could lead to unexpected outcomes.

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 sentence that directly conveys the core function. It is well-structured and free of unnecessary detail, 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 tool's simplicity, the description covers the basic purpose but lacks essential contextual information. It does not explain parameter semantics, return format, or how this tool relates to siblings like 'search' or 'ids'. This incompleteness hampers correct usage.

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 schema provides no descriptions for the three parameters, and the tool description does not explain them either. 'query' is mentioned but its format and syntax are undefined; 'account' and 'include_excluded' are completely unexplained. This leaves the agent unable to construct correct invocations.

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 action ('Return') and the object ('maildir file paths'), and specifies that results are based on a query. However, it does not elaborate on what constitutes a 'matching' query, leaving some ambiguity about the exact filtering criteria.

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 no guidance on when to use this tool versus its siblings (e.g., 'search', 'ids', 'show'). There is no mention of use cases, prerequisites, or scenarios where this tool is preferred, leaving the agent without direction on tool selection.

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 indicating side effects. 'List' implies a read-only operation, so it is transparent about non-destructive behavior, but it does not explicitly rule out side effects or mention any state changes.

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 sentence with no redundant words or unnecessary details. It is well-structured and 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 there is no output schema, the description adequately explains what data will be returned (accounts, folders, index tags, last sync, last error). It does not specify output structure or formatting, but the content is clear enough for basic usage.

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 no parameters, and the schema is empty. The baseline for zero parameters is 4, and the description does not need to add parameter details.

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 purpose with a specific verb ('List') and identifies the exact resources returned: accounts, folders, index tags, and last sync/error info. This distinguishes it from sibling tools like 'files' or 'show'.

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 does not provide explicit guidance on when to use this tool versus alternatives such as 'status', 'refresh', or 'show'. There is no mention of conditions or preferred use cases.

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 not disclose whether the tool is read-only, whether it has side effects, or any permissions/limitations. The behavior beyond returning IDs is unclear.

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, clear sentence with no unnecessary words. It is direct and to the point.

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 is minimal. It does not explain the return format (e.g., list of IDs, JSON structure) nor the meaning of optional parameters. Given the absence of an output schema, the description leaves significant gaps for the agent.

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 schema provides parameter names and types but no descriptions. The description only mentions the query parameter implicitly, leaving 'account' and 'include_excluded' unexplained. Coverage of parameter semantics is low.

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 function: returning message IDs matching a query. It is specific about the action and the resource (messages), but does not distinguish it from sibling tools like 'search' or 'count' without additional context.

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 guidance is provided on when to use this tool versus alternatives. It does not mention any conditions, prerequisites, or scenarios where this tool is preferred over siblings like 'search' or 'show'.

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 description discloses key side effects (syncing every folder, reindexing) and the waiting behavior up to 20 seconds, including a note about what happens if the pass is still running. This is transparent for a maintenance operation.

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 concise, with two sentences that front-load the primary action and include essential behavioral details. No redundant information.

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 low-complexity tool with one optional parameter and no output schema, the description covers the key scenarios: syncing, reindexing, waiting, and handling a still-running pass. It omits output details but those are not critical given the absence of an output 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?

The 'account' parameter is a string with no schema description, but the description text clarifies that it can target one account or all accounts. This partially compensates for the missing parameter metadata, though explicit per-parameter details would be better.

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 primary actions (sync folders and reindex) and scope (one account or all accounts). It does not explicitly differentiate from sibling tools like search or status, but the core purpose is 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 implies usage for forcing a sync/reindex and mentions waiting and retrying, but does not explicitly state when to prefer this over alternatives such as search or status. Some guidance is present but could be more 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 is the only behavioral indicator. It implies a read-only search operation but does not explicitly state side effects, permissions, 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?

The description is brief and information-dense, including the query syntax in one sentence. No unnecessary words or redundant details.

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 lacks explanations for parameters and output format beyond 'JSON'. It does not cover error handling, pagination, or parameter constraints, leaving many operational details unspecified.

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 0%, and the description does not explain any of the five parameters (limit, query, offset, account, include_excluded). This leaves the agent without guidance on how to set them.

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 searches mail and returns thread summaries as JSON, providing a specific verb and resource. It also gives the query syntax, making the purpose unmistakable.

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 query syntax but does not explain when to use this tool versus siblings like 'thread' or 'text'. No alternative guidance is 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?

With no annotations provided, the description carries the full burden of disclosing behavioral traits. It implies read-only behavior via 'show' but does not explicitly state side effects, errors, or access requirements.

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 sentence with no unnecessary words, front-loading the key action and output.

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 gives the general output but omits parameter meanings and any behavioral context, leaving the agent with insufficient information for correct invocation in varied scenarios.

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 0% for 4 parameters, and the description does not explain id, limit, offset, or include_excluded. The description must compensate for the missing schema details 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 specific action ('show one message'), the resource ('message'), and the output format ('headers and decoded body, as JSON'), distinguishing it from sibling tools like search, status, and text.

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?

There is no guidance on when to use this tool versus alternatives such as search or text, nor any indication of prerequisites or typical use cases.

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?

Although no annotations are provided, the description uses the verb 'report,' which strongly implies a read-only operation with no side effects. It also specifies what data is returned (messages indexed, errors), making the tool's behavior transparent.

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 concise, consisting of two sentences. It conveys all necessary information without any redundant or extraneous text, making it easy to parse and understand.

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 provides a complete picture: it lists the specific health metrics returned and states the condition under which to invoke the tool. Since there is no output schema, the description adequately covers what the tool does 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?

The tool has zero parameters, and the schema coverage is 100% with no additional parameters to explain. The absence of parameters is inherently clear from the schema, so no further description is 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's purpose: reporting sync health per account with specific metrics (first full sync, last successful sync, messages indexed, errors, backoff). The verb 'report' and the resource 'sync health' are specific, distinguishing it from siblings like search or show.

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?

Explicit guidance is given on when to call this tool: 'Call this when results look incomplete or to check whether the server is fully functional yet.' This leaves no ambiguity about its intended use case.

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 disclosing behavioral traits, but it only mentions the return value. It does not address side effects, permissions, rate limits, or whether the operation is read-only, though 'Return' weakly implies a read operation.

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 sentence with no unnecessary words. However, its brevity comes at the cost of omitting important parameter details, so it is efficient but not fully structured around key information.

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 covers the basic purpose but is incomplete for correct invocation: it does not explain the limit, offset, or include_excluded parameters, nor does it describe the output format. Given the low complexity, more detail should have been included.

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 schema includes four parameters (id, limit, offset, include_excluded), but the description only indirectly references 'id' via 'one message.' The meanings and effects of limit, offset, and include_excluded are entirely unexplained, and schema property descriptions are absent.

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 'Return' and the resource 'the plain-text body of one message,' with the additional detail of converting HTML. It distinguishes this tool from siblings like 'show' or 'attachment' by focusing on plain-text body extraction.

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 no explicit guidance on when to use this tool versus alternatives, nor does it mention prerequisites or context. It only states what the tool does, leaving usage decisions to inference.

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?

It discloses a key behavioral aspect — that junk/trash replies are excluded by default and that setting include_excluded includes them. This goes beyond the bare minimum, though it does not cover other behaviors like pagination limits or error handling, but given the absence of annotations, this is reasonably transparent.

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 concise sentences, front-loading the primary purpose and then adding the key behavioral nuance. No verbose or redundant phrasing.

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 no output schema, the description should clarify what the response contains or what constitutes a 'whole thread'. It does not. It also does not explain how 'id' identifies the message or whether related attachments are included. This is adequate for a simple tool but leaves room for interpretation.

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 descriptions are absent (0% coverage), so the description must compensate. It only clarifies the include_excluded parameter; 'id', 'limit', and 'offset' are left unexplained. 'id' is required and its purpose (presumably a message ID) is only implied, while limit/offset are not mentioned at all, leaving significant ambiguity.

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 shows the whole thread containing a message, with a specific verb ('show') and resource ('thread'). It distinguishes from siblings like 'files' and 'folders', though 'show' is a sibling that could overlap in purpose, but the context of 'thread' makes it clear enough.

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 explains the default behavior (excluding junk/trash replies) and how to override it with include_excluded, which gives some usage guidance. However, it does not explicitly compare against alternatives like 'show' or 'search', nor does it specify when to use this tool versus another.

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