emailmd

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

With no annotations, the description carries the full burden. It discloses that the tool does not render, lists specific checks, and adds a useful caveat about false positives. It does not describe the return format (e.g., structure of warnings), but overall behavior is well conveyed.

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 with no filler. Front-loaded with clear purpose, then concrete examples, then a practical caveat. Every word 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?

Given 2 parameters, 100% schema coverage, and no output schema, the description is largely complete. It explains what the tool checks, the non-rendering behavior, and the intentional-suggestion caveat. The only notable gap is the absence of explicit return value structure, but 'warnings' and 'suggestions' imply the nature of the output.

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% for both parameters, so the baseline is 3. The description adds some context about 'emailmd markdown' and YAML frontmatter, but it does not explain the 'partials' parameter, which is covered only by the 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 a specific verb+resource: 'Check emailmd markdown for deliverability, accessibility, and readability problems'. It explicitly differentiates from sibling 'render' by noting it does this 'without rendering it'.

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: use before sending to fix warnings, and notes that some suggestions are intentional (transactional emails). However, it does not explicitly mention alternatives like 'render' for previewing, missing an explicit when-not-to-use.

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 optional argument behavior and gives examples, but does not mention error handling or return format. For a simple read tool, this is adequate, though not fully exhaustive.

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: two sentences that front-load the core purpose and then provide usage examples and guidance. Every sentence contributes value without redundancy.

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 tool with one optional parameter and no output schema, the description fully covers purpose, usage, parameter semantics, and when to use it. It is complete enough for an agent to invoke correctly.

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 already provides a description for the 'page' parameter (pattern, examples, and 'Omit for the index'), so the description adds little beyond that. With 100% schema coverage, the baseline of 3 is appropriate.

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: 'Fetch emailmd documentation from emailmd.dev.' It uses a specific verb ('Fetch') and resource ('emailmd documentation'), and the distinction from siblings (lint, render) is evident, as those tools likely operate on the content rather than retrieve 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?

The description provides clear usage context: 'Call with no arguments for the index of all pages; pass page to read one' and 'Read the relevant page before using syntax you are not sure about.' While it lacks explicit alternatives or when-not-to-use instructions, the guidance is sufficient for a simple documentation fetcher.

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 transparency burden. It thoroughly discloses return values, including warnings for non-fatal repairs and previewUrl for live preview, giving a strong behavioral contract. It does not explicitly state side-effect freedom, but the nature of rendering makes this less critical.

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: the first delivers the core purpose, the second compactly enumerates return values. Every word earns its place, and it is front-loaded with the most important 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?

Since there is no output schema, the description must explain return values, and it does so thoroughly, listing all six output fields and their meanings. Minor gaps like error handling are less critical given the schema covers parameter constraints.

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%, so the schema already documents all parameters. The description adds context about the markdown format (emailmd, frontmatter) but does not elaborate on parameter details beyond the schema, matching the baseline for high schema 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 the tool's specific verb and resource: 'Render emailmd markdown into email-safe HTML.' It also lists detailed outputs, distinguishing it from sibling tools lint and read_docs, which serve different purposes.

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 is the rendering step but does not explicitly state when to use it versus alternatives like lint or read_docs, nor does it mention prerequisites or exclusions. Context is clear but guidance on selection is absent.

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