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

Annotations only declare readOnlyHint and openWorldHint; the description carries all the real behavioral weight — fetch limits (12 sheets, 2 MB per response, 8 s timeout), the reduced-motion-safe badge precondition, the not-measurable path, and the review-vs-violation distinction. It also discloses that network I/O occurs, 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?

Purpose is front-loaded, then constraints, return shape, and caveats in a logical order, with no filler sentences. It is dense but long, and 'Uses scoring v2. Same engine and scoring as the free site check' is mildly redundant.

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 enumerates the returned fields (ok, url, status, score, findings, groups, summary, badge, coverage) and the error shape with isError:true. Combined with the documented failure and not-measurable modes, an agent has everything needed to call and interpret 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?

Only one parameter, and the schema already documents it at 100% coverage as the http/https page URL. The description adds fetch side constraints (sheet count, response size, timeout) that shape expectations but don't add meaning to the url argument itself, so the baseline 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 opens with a specific verb+resource: a static motion-a11y checker that fetches a URL's HTML and linked stylesheets and scans CSS for four enumerated motion issues. It is unmistakable next to non-overlapping siblings (motion_catalog, motion_compile, motion_stats, motion_validate), none of which are URL auditors.

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 states clear scope boundaries and exclusions: runtime motion (WAAPI/GSAP/WebGL) is not audited, loading indicators are 'review' not violations, and pages without CSS motion yield status 'not-measurable' with score null. It also tells the agent to read status first. It does not explicitly route to an alternative tool for runtime motion, so it falls short of a full 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 declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds useful behavioral context: this is a discovery/priming tool that must precede authoring, and it returns structured reference data rather than performing any operation. It doesn't discuss size of the catalog or pagination, which would have completed the picture.

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 tool-relevant content is front-loaded and efficient: one sentence of purpose, one sentence of workflow. However, the trailing 'Free motion check' URL and 'paid Motion Report (9 USD)' pricing link are promotional rather than functional, adding noise an agent must filter when deciding whether to call the tool.

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 parameters, the description carries the burden of describing return content, and it does so by naming the catalog fields. Combined with the explicit sequencing into motion_validate and motion_compile, an agent has enough to call this correctly. The only omission is any sense of catalog size or response format.

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 the baseline is 4. The description does earn some credit by describing what the (absent) output schema would otherwise document — the returned catalog fields — helping the agent anticipate the result shape.

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 and resource ('Returns the catalog of verified motion primitives') and enumerates exactly what's inside (names, purpose, parameter schemas, defaults), plus the authoring rules for writing a MotionSpec. This is clearly distinguishable from siblings like motion_validate or motion_compile, which act on a spec rather than supply the vocabulary for authoring one.

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 an explicit ordered workflow: 'Call this FIRST, then write the spec yourself, check it with motion_validate and compile it with motion_compile.' It names both alternative tools and the precise step at which each applies, leaving no inference needed about sequencing.

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 readOnly/idempotent/non-destructive/closed-world, and the description adds substantive behavioral detail on top: fail-closed validation, deterministic output, reduced-motion default, a performance-budget report, and the accessibility-warning caveat. It also explicitly states non-effects (no file writes, no code execution), which is exactly the kind of context annotations can't convey.

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?

Front-loaded with the core action and result, then return shape, then caveats. It's dense but nearly every clause carries information; the return-shape enumeration is slightly bulky but justified given there's no output 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?

With no output schema, the description fully specifies the return contract ({ok:true,...} vs {ok:false,...}, css nullable) plus error semantics and side-effect boundaries. Nothing an agent needs to invoke this correctly and interpret results is missing.

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 both parameters are already documented in the schema and the baseline applies. The description adds no detail about the MotionSpec object's internal shape or the specName header behavior beyond what the schema states, so it neither compensates nor detracts.

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 a specific verb pair ("Validates and deterministically compiles") and a concrete resource transformation (MotionSpec → vanilla-GSAP JS and CSS). It distinguishes itself from the sibling validate/audit tools by emphasizing compilation output, so an agent can tell what this tool uniquely produces.

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 implied usage guidance ("Read warnings before shipping", "Does not write files or execute the emitted code") but never explicitly says when to pick this over motion_validate or motion_audit. An agent must infer the routing from the stated output shape rather than from an explicit when-to-use statement.

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 readOnlyHint=true (safe read) and openWorldHint=false. The description adds meaningful behavioral context: it returns aggregated counts per outcome and identifies escalation clusters for catalog needs. This goes beyond the annotations without contradicting them.

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 concise with two sentences and no unnecessary words. It is front-loaded with the core purpose ('Summary of routing/compile telemetry') and efficiently conveys the key 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?

Given there is no output schema, the description adequately describes the return content (counts per outcome, escalation clusters). However, for a telemetry tool, it might be improved by clarifying the time period or data scope, though it is sufficient for basic use.

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 with 100% schema coverage (empty object). There are no parameters to document, so the description need not add parameter information. Baseline score of 4 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 it provides a summary of routing/compile telemetry with counts per outcome and escalation clusters indicating catalog needs. However, it does not explicitly differentiate from sibling tools like motion_audit or motion_catalog, which could share similar 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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of prerequisites, limitations, or comparison with sibling tools. The description only states what it does without any usage 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?

The description goes well beyond the readOnlyHint and openWorldHint annotations by disclosing fail-closed behavior, the exact return shape, and the non-obvious fact that warnings can be non-empty while ok=true. It also explains the accessibility implication, which is critical for correct agent 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?

The description is compact and front-loaded, with the core validation behavior stated first, followed by the return shape and the critical warning caveat. Every sentence earns its place, and the formatting highlights the most important behavioral nuance.

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 single-parameter, read-only validation tool with no output schema, the description fully covers what the tool does, when to use it, what it returns, and the key failure and warning semantics. An agent has sufficient information to select and invoke it correctly without additional context.

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 for the single parameter is 100%, so the baseline is 3. The description adds meaningful semantics by clarifying that the spec parameter is a MotionSpec and by enumerating the validation dimensions applied to it, such as the primitive allow-list and injection rules, which the schema alone does not convey.

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 a specific verb ('Checks') and a specific resource ('MotionSpec'), then enumerates exactly what it validates against: schema, primitive allow-list, parameter bounds, and injection rules. It clearly distinguishes itself from the sibling motion_compile by positioning validation as a pre-compile safety check.

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 explicitly says 'Use to pre-check a spec before compiling,' which gives clear guidance on when to call this tool. It also explains the important warning behavior so an agent knows this is the right tool for accessibility checks before compilation, though it does not explicitly name or exclude alternatives beyond the pre-compile framing.

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