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

Annotations say readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true, which is otherwise puzzling for an 'acknowledge' tool. The description resolves the tension by explaining the change is local-only with 'no server mutation', and adds a sequencing precondition. It still omits what happens on premature acknowledge or failure/retry behavior.

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 effect and the safety clarification, then the precondition. Every clause carries information; nothing is padding.

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's behavioral profile is adequately covered for a local-state mutation with no output schema, and the precondition is given. However, with 0% parameter documentation and no output schema, the agent is left guessing what 'folder' and 'receipt' actually contain, which is a real gap for 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 description coverage is 0% for both required parameters ('folder', 'receipt'), so the description must compensate but does not define either. 'Receipt' is only implicitly a confirmation token and 'folder' is not explained at all, despite the description referencing checkpoint advancement. Low coverage with no compensating detail.

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 (acknowledge/confirm) and its effect: advancing a LOCAL checkpoint, plus explicitly negating server mutation. This is distinguishable from siblings like check_incremental and list_folders. It loses a point only because 'durable downstream processing' is vague jargon that the agent must interpret.

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?

Gives a clear precondition: 'Acknowledge only after every UID is handled or recorded as unavailable.' That is actionable when-to-use guidance. It does not name an alternative tool or an explicit when-not-to-use case, so it stops short of a 5.

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 supply the safety profile (readOnly, idempotent, non-destructive, open world). The description adds genuine behavioral context by naming the checkpoint identity ('folder + UIDVALIDITY + UID'), which is not in any structured field. However, it says nothing about what 'replay' yields, how limit affects the batch, or how this interacts with acknowledge_checkpoint; the 'create' verb also sits in mild tension with readOnlyHint.

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 terse sentences, operation stated first, identity scope second. No padding or redundancy; the only knock is that the compression makes the content opaque rather than 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?

With no output schema and no schema parameter descriptions, the description needs to do more for a stateful incremental-sync tool. It omits return content, pagination behavior via limit, and the relationship to acknowledge_checkpoint, leaving the agent unable to call it correctly beyond guessing.

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%, so the description must carry the load. It implicitly scopes the operation to a folder via the identity string, but never explains folder's role or what limit (1-100, default 50) controls. Only one of two parameters gets any illumination.

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 names a verb+object ('Replay unacknowledged UID batch or create next batch'), but 'batch' and 'replay' are jargon that never resolve into what the tool actually returns or operates on. It gestures at an incremental mail-sync role distinct from search_mail/read_mail, but the agent cannot confidently map it to a task from this text alone.

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 when-to-use or when-not-to-use guidance, and no mention of the sibling acknowledge_checkpoint, which is clearly the paired tool (acknowledged vs unacknowledged batches). The agent must infer the entire 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?

Annotations already declare readOnly, idempotent and non-destructive, so the safety profile is covered. The phrase 'selectable and nonselectable' hints that folders carry a selectability attribute, but nothing is said about pagination, ordering, or hierarchy depth.

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?

A single front-loaded sentence with no filler. Nothing could be trimmed without losing 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 trivial, parameterless, read-only listing tool with annotations covering the safety profile, this is close to adequate, but it never describes what a returned folder looks like or what the selectability flag means to a caller.

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 takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 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?

States a specific verb+resource (list folders) and even narrows the scope to two categories of folder. It is easily distinguished from the mail-oriented siblings, though the 'selectable vs nonselectable' distinction is left unexplained.

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 when-to-use guidance, no prerequisites, no indication of what a caller does with the result (e.g., feeding folder IDs into another tool). Usage is only implied by the verb.

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 cover the safety profile (readOnly, idempotent, non-destructive), so the description's added value is real: PEEK discloses that reading does not mutate the \Seen flag, and the untrusted-data warning is an important security behavior for MIME/HTML payloads. It does not cover error cases or rate/connection limits, keeping it below a 5.

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, no filler, with the operation stated first and the safety caveat second. Every clause 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?

With no output schema, the description does hint at the return contents (MIME and HTML), which helps, but it leaves the parameter contract and failure behavior unexplained for a 3-required-param tool. Adequate but with clear gaps.

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?

Three required parameters with 0% schema description coverage, so the description carries the full burden, yet it only mentions the UID and says nothing about folder semantics or the string-typed uidvalidity. A caller must infer formats and the relationship between these three values.

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 (Read) and resource (a mail message identified by UID), plus the IMAP mechanism (PEEK), which is enough for an agent to distinguish it from search_mail and list_folders. It stops short of explicitly naming the siblings or the scope it covers.

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 choose this tool over search_mail or list_folders, and no mention of the prerequisite of obtaining folder/uidvalidity first. Usage is only implied by the verb.

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 cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower, yet the description still adds real behavior: ascending UID ordering, inclusive/exclusive date boundaries, IMAP internal-date basis, and the persisted-snapshot resume semantics. These are non-obvious traits an agent could not infer from the annotations or schema.

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?

It is a single dense, front-loaded block with no filler sentences; every clause carries information. The telegraphic, fragmentary style slightly hurts readability, which keeps it from a 5.

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 7-parameter, 0%-schema-coverage search tool with no output schema, the description never mentions the core filtering capability (folder, sender, subject) or the limit parameter. It gives strong date/cursor semantics but leaves the tool's primary use case and half its parameters unexplained.

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 0% across 7 parameters, so the description must compensate. It does so well for since/before (format and inclusive/exclusive semantics) and cursor (resume overrides other filters), but folder, sender, subject, and limit are entirely undocumented in both schema and description, leaving most filtering parameters opaque.

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 name search_mail supplies the verb+resource, but the description opens with the cryptic 'Snapshot ascending UIDs' and never says it searches/filters mail. It conveys ordering and cursor behavior rather than a clear statement of what the tool returns, and it does not distinguish itself from read_mail or check_incremental. Purpose is only implied, not stated.

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 when-to-use guidance and no reference to alternatives like read_mail or list_folders. The only conditional guidance is internal cursor-resume behavior ('other filters are ignored on resume'), which is about mechanics, not about when to pick this tool over its siblings.

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